Previous Article | Next Article ![]()
Journal of Bacteriology, September 1998, p. 4387-4391, Vol. 180, No. 17
Institut für Mikrobiologie,
Westfälische Wilhelms-Universität Münster, D-48149
Münster, Germany
Received 25 March 1998/Accepted 7 June 1998
The coniferyl aldehyde dehydrogenase (CALDH) of
Pseudomonas sp. strain HR199 (DSM7063), which catalyzes the
NAD+-dependent oxidation of coniferyl aldehyde to ferulic
acid and which is induced during growth with eugenol as the carbon
source, was purified and characterized. The native protein exhibited an apparent molecular mass of 86,000 ± 5,000 Da, and the subunit mass was 49.5 ± 2.5 kDa, indicating an Pseudomonas sp. strain
HR199 is able to grow with eugenol as the sole carbon and energy
source. Eugenol, which is the main component of the essential oil of
the clove tree, Syzygium aromaticum, is most probably
degraded via coniferyl alcohol, coniferyl aldehyde, ferulic acid,
vanillin, and vanillic acid to protocatechuic acid (16, 26,
27), which is further metabolized by ortho cleavage (23). Coniferyl aldehyde is also described as an
intermediate in the catabolism of eugenol by a
Corynebacterium sp. (35) and a
Pseudomonas sp. (36) and in the catabolism of
coniferyl alcohol by Rhodococcus erythropolis (6)
and a Xanthomonas sp. (13).
We are currently investigating the catabolism of eugenol by
Pseudomonas sp. strain HR199 in detail, since there is an
interest in producing vanillin by biotransformation of this natural raw material. One important step in this biotransformation is the oxidation
of coniferyl aldehyde to ferulic acid (Fig.
1), which is catalyzed by coniferyl
aldehyde dehydrogenase (CALDH). This enzyme has not been purified
before, and there are no detailed molecular data available for such a
dehydrogenase. In the present study, we describe the purification of
the NAD+-dependent CALDH of Pseudomonas sp.
strain HR199 and the molecular characterization of the corresponding
structural gene, calB.
0021-9193/98/$04.00+0
Copyright © 1998, American Society for Microbiology. All rights reserved.
Purification and Characterization of the Coniferyl
Aldehyde Dehydrogenase from Pseudomonas sp. Strain HR199 and
Molecular Characterization of the Gene
![]()
ABSTRACT
Top
Abstract
Introduction
Materials & Methods
Results
Discussion
References
2 structure
of the native enzyme. The optimal oxidation of coniferyl aldehyde to
ferulic acid was obtained at a pH of 8.8 and a temperature of 26°C.
The Km values for coniferyl aldehyde and
NAD+ were about 7 to 12 µM and 334 µM, respectively.
The enzyme also accepted other aromatic aldehydes as substrates,
whereas aliphatic aldehydes were not accepted. The
NH2-terminal amino acid sequence of CALDH was determined in
order to clone the encoding gene (calB). The corresponding
nucleotide sequence was localized on a 9.4-kbp EcoRI
fragment (E94), which was subcloned from a Pseudomonas sp. strain HR199 genomic library in the cosmid pVK100. The partial sequencing of this fragment revealed an open reading frame of 1,446 bp
encoding a protein with a relative molecular weight of 51,822. The
deduced amino acid sequence, which is reported for the first time for a
structural gene of a CALDH, exhibited up to 38.5% amino acid identity
(60% similarity) to NAD+-dependent aldehyde dehydrogenases
from different sources.
![]()
INTRODUCTION
Top
Abstract
Introduction
Materials & Methods
Results
Discussion
References

View larger version (12K):
[in a new window]
FIG. 1.
CALDH, encoded by calB, catalyzes the
NAD+-dependent oxidation of coniferyl aldehyde to ferulic
acid.
| |
MATERIALS AND METHODS |
|---|
|
|
|---|
Bacterial strains, plasmids, and growth conditions. Cells of Pseudomonas sp. strain HR199 (DSM 7063) (27) were grown at 30°C either in a nutrient broth medium (0.8%, wt/vol; Bacto, Difco) or in mineral salts medium (MM or HR-MM [27, 30]) supplemented with carbon sources as indicated in the text. Coniferyl alcohol, coniferyl aldehyde, and ferulic acid were dissolved in dimethyl sulfoxide and were added to the medium at a final concentration of 0.1% (wt/vol). Eugenol was directly added to the medium at a final concentration of 0.1% (vol/vol). For mass cultivation, cells were grown aerobically in 20-liter fermentors (type F0020; CHEMAP AG, Männedorf, Switzerland) containing 15 liters of HR-MM supplemented with 0.5% (wt/vol) gluconate and 0.1% (vol/vol) eugenol. Growth was monitored photometrically at 436 nm. Samples were taken and catabolic intermediates were analyzed by high-performance liquid chromatography as described previously (26). If exhausted, eugenol was added to the culture to a final volume of 0.1% (vol/vol). Cells were harvested at a turbidity of about 6 when coniferyl alcohol, coniferyl aldehyde, and ferulic acid were still detectable in the medium.
Cells of Escherichia coli XL1-Blue (3) harboring hybrid plasmids of pBluescript SK(
) (Stratagene, San Diego, Calif.)
or of E. coli S17-1 (32) harboring hybrid
plasmids of pVK101 (14) were grown at 37°C in
Luria-Bertani (LB) medium or in M9 mineral salts medium
(29), both containing tetracycline or ampicillin at final
concentrations of 12.5 and 100 µg/ml, respectively.
Qualitative and quantitative determination of catabolic intermediates. Analysis of culture supernatants for excreted intermediates of the eugenol catabolism was performed by liquid chromatography without prior extraction, as described previously (26).
Preparation of the soluble fraction of the crude extract. The cells were disrupted by a twofold French press passage at 96 MPa. The soluble fraction of the crude extract was obtained by centrifugation at 100,000 × g at 4°C for 1 h.
Enzyme assay.
CALDH was assayed photometrically at 400 nm at
26°C in 100 mM Tris-HCl buffer, pH 8.8, in the presence of 2.7 mM
NAD+ and 0.08 mM coniferyl aldehyde by measuring the
initial absorbancy changes due to the consumption of coniferyl aldehyde
(
= 34 cm2 µmol
1) or at 340 nm by
measuring the initial absorbancy changes due to the formation of NADH
(
= 6.3 cm2 µmol
1).
Purification of CALDH. All steps were carried out at 4°C with 10 mM sodium phosphate buffer (pH 7). A soluble fraction of a crude extract (about 3 g of protein) was derived from about 55 g of wet cells, dialyzed for 12 h against buffer, and then applied to a column (120-ml bed volume [BV]) of DEAE-Sephacel equilibrated with buffer. The column was washed with 2.5 BVs of buffer, and the bound proteins were eluted with a linear NaCl gradient (0 to 500 mM; 600 ml) at a flow rate of 2 ml/min. Fractions (10 ml each) exhibiting high CALDH activity were combined and dialyzed for 4 h against buffer. The enzyme solution was then applied onto a buffer-equilibrated column (80-ml BV) of hydroxylapatite. CALDH did not bind to this matrix and was eluted with 250 ml of buffer at a flow rate of 2 ml/min, whereas other proteins bound to the matrix under these conditions. Fractions (10 ml each) exhibiting high CALDH activity were combined and concentrated by ultrafiltration in a Diaflo chamber equipped with a YM 30 membrane. The enzyme solution was then applied onto a buffer-equilibrated Superdex 200 HiLoad 26/60 column (330-ml BV), at a flow rate of 1 ml/min. CALDH was eluted after a retention volume of 160 ml was reached. Fractions (2 ml each) exhibiting high CALDH activity were combined.
Molecular weight determination by gel filtration.
A Superdex
200HR 10/30 column (24-ml BV; Pharmacia LKB Biotechnologie) was
equilibrated with 2.5 BVs of buffer. Purified CALDH and calibration
proteins (1.0 mg each) were applied onto the column at a flow rate of
0.5 ml/min. Relative molecular masses were calculated from
semilogarithmic plots of the molecular masses of the calibration proteins (bovine serum albumin, yeast alcohol dehydrogenase, sweet potato
-amylase, and horse spleen apoferritin [Sigma, Deisenhofen, Germany]) against the elution volume.
Electrophoretic methods. Proteins were separated under denaturing conditions in 11.5% (wt/vol) polyacrylamide gels by the method of Laemmli (17) and stained with Serva Blue R.
N-terminal sequence analysis. N-terminal sequence analysis was performed as described in detail previously (24).
Transformation of DNA. Competent cells of E. coli were prepared and the DNA was transformed by using the CaCl2 procedure as described by Hanahan (8).
DNA sequence determination and analysis.
The nucleotide
sequences were determined nonradioactively with a model 4000L DNA
sequencer (LI-COR Inc., Biotechnology Division, Lincoln, Nebr.) and a
Thermo Sequenase fluorescence-labelled primer cycle sequencing kit with
7-deaza-dGTP (Amersham Life Science, Amersham International plc, Little
Chalfont, Buckinghamshire, United Kingdom) according to the
instructions of the manufacturers. Fragment E94 was isolated and
digested with Sau3a and HaeIII. The resulting
subfragments were cloned in pBluescript SK(
), and the corresponding
hybrid plasmids were used as template DNA together with the universal
and reverse sequencing primers. Additional sequences were obtained with
synthetic fluorescence-labelled oligonucleotides as primers, by the
primer-hopping strategy (34). Nucleotide and amino acid
sequences were analyzed with the Genetic Computer Group sequence
analysis software package (version 6.2; June 1990) by the method of
Devereux et al. (5).
Nucleotide sequence accession number. The nucleotide sequence and amino acid sequence data reported in this paper have been submitted to the EMBL, GenBank, and DDBJ nucleotide sequence databases under accession no. AJ006231.
| |
RESULTS |
|---|
|
|
|---|
Purification of CALDH. The CALDH from eugenol-grown cells of Pseudomonas sp. strain HR199 was purified 79-fold in a three-step procedure (Table 1). The soluble fraction of the crude extract exhibited a specific CALDH activity of 0.46 U/mg of protein. Chromatography on DEAE-Sephacel resulted in a 6.5-fold increase of the specific activity, with a 65% recovery of the enzyme activity. The subsequent chromatography on hydroxylapatite resulted in a 69.7-fold increase of the specific activity, with a 34% recovery of the enzyme activity. The final gel filtration chromatography on a Superdex 200 HiLoad 26/60 column resulted in a 79-fold increase of the specific activity, with a 13% recovery of the enzyme activity. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) of the purified enzyme revealed only a single band corresponding to the subunit of CALDH (Fig. 2).
|
|
Properties of CALDH. SDS-PAGE of purified CALDH resulted in one band, indicating the presence of only one type of subunit, with an apparent molecular weight (Mr) of 49,500 ± 2,500 (Fig. 2). The nondenatured protein exhibited an apparent Mr of 86,000 ± 5,000 as revealed by gel filtration. These results indicated a homodimeric structure of the native CALDH.
The optimum pH for the NAD+-dependent oxidation of coniferyl aldehyde to ferulic acid catalyzed by CALDH was 8.8 in 100 mM Tris-HCl buffer. However, at this pH the enzyme was quite unstable and lost 87% of its activity within 5 min. Even at a pH of 7.5 the CALDH activity was reduced to 50% within 10 min. At a pH of 6.0 the loss of enzymatic activity was less dramatic, and 50% of the initial activity was left after 4 h. The optimum temperature for the NAD+-dependent oxidation of coniferyl aldehyde to ferulic acid catalyzed by CALDH was 26°C, and the stability of the enzyme drastically decreased at increasing temperatures. The half-lives of CALDH activity at 31, 34, and 38°C were 5, 2.5, and 1 min, respectively. At temperatures higher than 46°C, the enzyme had a total loss of activity within less than 1 min. For coniferyl aldehyde and NAD+, Km values of 7 to 12 µM and 0.334 mM, respectively, were calculated from Lineweaver-Burk plots. NADP+ was used as an electron acceptor at 4.3% of the rate of NAD+ reduction. In addition to coniferyl aldehyde, trans-cinnamaldehyde, sinapyl aldehyde, and benzaldehyde were substrates of the enzyme, with maximum rates of about 97, 77, and 18% relative to coniferyl aldehyde, respectively, whereas acrolein and vanillin were not oxidized by the enzyme. The NH2-terminal amino acid sequence of CALDH was determined by Edman degradation to be 1-Ser-Ile-Leu-Gly-Leu-Asn-Gly-Ala-Pro-Val-Gly-Ala-Glu-Gln-Leu-Gly-Ser-Ala-Leu-19.Induction of CALDH activity during growth on eugenol. Pseudomonas sp. strain HR199 is able to utilize eugenol as the sole carbon source for growth. Cells grown on this substrate exhibited a specific CALDH activity of about 0.5 U/mg of protein, whereas no CALDH activity was detectable in cells grown on gluconate. Therefore, the expression of the structural gene of CALDH (calB) seems to be specifically induced during growth on eugenol. This result indicates that coniferyl aldehyde represents an intermediate in the catabolism of eugenol by Pseudomonas sp. strain HR199.
Identification and cloning of the structural gene of CALDH (calB). During our group's investigations of the eugenol catabolism by Pseudomonas sp. strain HR199, complementation of a CALDH-deficient mutant was achieved with a hybrid cosmid (pE5-1) from a genomic library in pVK100 (16). This hybrid cosmid harbored five EcoRI fragments with sizes of 1.2, 1.8, 3.0, 5.8, and 9.4 kbp (E12, E18, E30, E58, and E94, respectively). Comparison of the NH2-terminal amino acid sequence obtained from the purified CALDH with amino acid sequences deduced from partial nucleotide sequences of these fragments revealed the localization of the CALDH structural gene (calB) on fragment E94, whereas the structural gene of the coniferyl alcohol dehydrogenase (calA) corresponded to a region covered by fragments E12 and E18 (16).
Nucleotide sequence of calB.
To determine the nucleotide
sequence of calB, fragment E94 and HpaI and
Sau3a subfragments of E94 were cloned separately in pBluescript SK(
). First, nucleotide sequence data were obtained by
using the universal and the reverse sequencing primers together with
the aforementioned hybrid plasmids as template DNA. To complete the
nucleotide sequences of calB and of adjacent regions,
specific synthetic fluorescence-labelled oligonucleotides were applied as primers together with E94 cloned in pBluescript SK(
) as template DNA. The DNA sequence of this 2,000-bp region exhibited a G+C content
of 55.1 mol%. An open reading frame of 1,446 bp, which was referred to
as calB, was identified. Its putative translational start
codon (ATG) at position 375 was preceded by a putative Shine-Dalgarno sequence (AGGAGGT) at a distance of five nucleotides. There
was a stem loop structure (CGGGCCCAGGAGC-ATGC-GCTTCTGGGCCCG)
22 bp downstream of the calB gene, which was followed
by a T-rich sequence, possibly representing a factor-independent
transcriptional terminator. The free energy of this structure is
approximately
90 kJ/mol, according to Tinoco et al. (37).
The G+C content of calB was 56.6 mol% and the biases of the
G+C contents for the different codon positions corresponded well with
the theoretical values calculated according to the method of Bibb et
al. (1). In addition, the codon usage of calB was
very similar to the codon usages of other sequenced genes of
Pseudomonas sp. strain HR199 (16, 23, 26). These
data indicated that calB represented a coding region.
Properties of the calB gene product. The relative molecular weight of the protein, calculated from the amino acid sequence deduced from the calB gene, was 51,953. This value corresponded well with the apparent molecular weight of 49,500 ± 2,500 determined by SDS-PAGE for the CALDH purified from Pseudomonas sp. strain HR199. Comparison of the amino acid sequence of CALDH with those in the GenBank database revealed homologies with aldehyde dehydrogenases (ALDHs) from different sources. The alignment of the amino acid sequence of CALDH from Pseudomonas sp. strain HR199 with those of nine representative ALDHs is shown in Fig. 3.
|
| |
DISCUSSION |
|---|
|
|
|---|
Pseudomonas sp. strain HR199 is able to utilize eugenol, which is catabolized via coniferyl alcohol and coniferyl aldehyde as the sole carbon source for growth (27). Coniferyl aldehyde is oxidized to ferulic acid in an NAD+-dependent reaction catalyzed by CALDH. The corresponding gene is expressed only in the presence of coniferyl aldehyde or substrates which are catabolized via this intermediate (e.g., eugenol). No expression is achieved in the presence of unrelated substrates, such as gluconate (16).
This is the first report on the purification of CALDH and the cloning and molecular characterization of the corresponding gene, calB. The CALDH purified from cells of Pseudomonas sp. strain HR199 grown in the presence of eugenol exhibited a specific activity of about 37 U/mg of protein, corresponding to an 80-fold enrichment compared to the soluble fraction of the crude extract. The enzyme showed a high affinity for the substrate coniferyl aldehyde (Km = 7 to 12 µM), combined with a broad substrate specificity towards propenal-substituted aromatic compounds. Nonaromatic aldehydes like propionaldehyde or 2-propenal (acrolein) were not accepted as substrates. Such relatively low Km values for the corresponding substrates are shared by the majority of ALDHs characterized so far, e.g., the 2-hydroxymuconic semialdehyde dehydrogenase from Pseudomonas putida (Km, 17 ± 6 µM [11]), the acetaldehyde dehydrogenase from Saccharomyces cerevisiae (Km, 20 µM [28]), the acetaldehyde dehydrogenase II from Alcaligenes eutrophus (Km, 4 µM [12]), and the human liver mitochondrial ALDH (Km for the propionaldehyde, 0.53 µM [31]). For NAD+, the CALDH exhibited a Km value of 310 µM, which was of the same order of magnitude as those reported for the benzaldehyde dehydrogenases from Acinetobacter calcoaceticus (250 µM [20]) and P. putida (330 ± 13 µM [11]) and acetaldehyde dehydrogenase II from A. eutrophus (200 µM [12]). Moreover, CALDH shared a broad substrate specificity with most of the other ALDHs.
The structural gene calB, encoding CALDH, was localized on an EcoRI fragment harbored by a hybrid cosmid, which was capable of complementing a mutant of Pseudomonas sp. strain HR199 that does not grow with eugenol as the sole carbon and energy source. The amino acid sequence deduced from calB showed significant homology to NAD+-dependent ALDHs from different sources (Fig. 3). Interestingly, CALDH exhibited greater homologies to ALDHs preferring aliphatic aldehydes as substrates than to ALDHs catalyzing the dehydrogenation of benzaldehyde or substituted benzaldehydes. This might reflect that the propenal moiety of coniferyl aldehyde is the target site of CALDH. Nevertheless, the aromatic nature of the substrate is essential for CALDH activity. Recently, the three-dimensional structures of the tetrameric enzyme bovine liver mitochondrial ALDH (33) and a dimeric class 3 ALDH (18) have been determined. These investigations together with detailed site-directed mutagenesis experiments involving exchange of conserved amino acids in human liver mitochondrial ALDH (31) confirmed that Cys-302 (positions are given according to the amino acid sequence of human liver mitochondrial ALDH [9]) is the active-site nucleophile (7) and that Glu-268 is the general locus of a charge relay triad (including a water molecule [33]) for the activation of Cys-302 by ionization (38). These residues were likely conserved in the amino acid sequence of CALDH (Cys-255 and Glu-221). The conservation of other amino acid residues was most probably due to other catalytic and structural requirements, as investigated in detail by Hempel et al. (10) and Sheikh et al. (31).
| |
ACKNOWLEDGMENTS |
|---|
Amino-terminal sequence analysis of the CALDH protein by Bernhard Schmidt from the Zentrum Biochemie, Abteilung Biochemie II der Georg-August-Universität zu Göttingen, Göttingen, Germany, and skillful technical assistance with DNA sequencing by Daniela Rehder are gratefully acknowledged.
H.P. and A.S. are indebted to Haarmann & Reimer GmbH for providing a collaborative research grant.
| |
FOOTNOTES |
|---|
* Corresponding author. Mailing address: Institut für Mikrobiologie, Westfälische Wilhelms-Universität Münster, Corrensstraße 3, D-48149 Münster, Germany. Phone: 49-251-8339829. Fax: 49-251-8338388. E-mail: priefer{at}uni-muenster.de.
| |
REFERENCES |
|---|
|
|
|---|
| 1. | Bibb, M. J., P. R. Findlay, and M. W. Johnson. 1984. The relationship between base composition and codon usage in bacterial genes and its use for the simple and reliable identification of protein-coding sequences. Gene 30:157-166[Medline]. |
| 2. | Boyed, L. A., L. Adam, L. E. Pelcher, A. McHughen, R. Hirji, and G. Selvaraj. 1991. Characterization of an Escherichia coli gene encoding betaine aldehyde dehydrogenase (BADH): structural similarity to mammalian ALDHs and plant BADH. Gene 103:45-52[Medline]. |
| 3. | Bullock, W. O., J. M. Fernandez, and J. M. Stuart. 1987. XL1-Blue: a high efficiency plasmid transforming recA Escherichia coli strain with beta-galactosidase selection. BioTechniques 5:376-379. |
| 4. |
Denome, S. A.,
D. C. Stanley,
E. S. Olson, and K. D. Young.
1993.
Metabolism of dibenzothiophene and naphthalene in Pseudomonas strains: complete DNA sequence of an upper naphthalene catabolic pathway.
J. Bacteriol.
175:6890-6901 |
| 5. | Devereux, J., P. Haeberli, and O. Smithies. 1984. A comprehensive set of sequence analysis programs for the VAX. Nucleic Acids Res. 12:387-395. |
| 6. | Eggeling, L., and H. Sahm. 1980. Degradation of coniferyl alcohol and other lignin-related aromatic compounds by Nocardia sp. DSM 1069. Arch. Microbiol. 126:141-148. |
| 7. | Farrés, J., T. T. Y. Wang, S. J. Cunningham, and H. Weiner. 1995. Investigation of the active site cysteine residue of rat liver mitochondrial aldehyde dehydrogenase by site-directed mutagenesis. Biochemistry 34:2592-2598[Medline]. |
| 8. | Hanahan, D. 1983. Studies on transformation of Escherichia coli with plasmids. J. Mol. Biol. 166:557-580[Medline]. |
| 9. | Hempel, J., R. Kaiser, and H. Jörnvall. 1985. Mitochondrial aldehyde dehydrogenase from human liver. Primary structure, differences in relation to the cytosolic enzyme, and functional correlations. Eur. J. Biochem. 153:13-28[Medline]. |
| 10. | Hempel, J., H. Nicholas, and R. Lindahl. 1993. Aldehyde dehydrogenases: widespread structural and functional diversity within a shared framework. Protein Sci. 2:1890-1900[Medline]. |
| 11. |
Inoue, J.,
J. P. Shaw,
M. Rekik, and S. Harayama.
1995.
Overlapping substrate specificities of benzaldehyde dehydrogenase (the xylC gene product) and 2-hydroxymuconic semialdehyde dehydrogenase (the xylG gene product) encoded by TOL plasmid pWW0 of Pseudomonas putida.
J. Bacteriol.
177:1196-1201 |
| 12. | Jendrossek, D., A. Steinbüchel, and H. G. Schlegel. 1987. Three different proteins exhibiting NAD-dependent acetaldehyde dehydrogenase activity from Alcaligenes eutrophus. Eur. J. Biochem. 167:541-548[Medline]. |
| 13. | Kern, H. W., L. E. Webb, and L. Eggeling. 1984. Characterization of a ligninolytic bacterial isolate: taxonomic relatedness and oxidation of some lignin related compounds. Syst. Appl. Microbiol. 5:433-447. |
| 14. | Knauf, V. C., and E. W. Nester. 1982. Wide host range cloning vectors: a cosmid clone bank of an Agrobacterium Ti plasmid. Plasmid 8:45-54[Medline]. |
| 15. |
Kok, M.,
R. Oldenhuis,
M. P. G. van der Linden,
C. H. C. Meulenberg,
J. Kingma, and B. Witholt.
1989.
The Pseudomonas oleovorans alkBAC operon encodes two structurally related rubredoxins and an aldehyde dehydrogenase.
J. Biol. Chem.
264:5442-5451 |
| 16. | Kresse, A. U., H. Priefert, and A. Steinbüchel. Unpublished results. |
| 17. | Laemmli, U. K. 1970. Cleavage of structural proteins during the assembly of the head of bacteriophage T4. Nature (London) 227:680-685[Medline]. |
| 18. | Liu, Z.-J., Y.-J. Sun, J. Rose, Y.-J. Chung, C.-D. Hsiao, W.-R. Chang, I. Kuo, J. Perozich, R. Lindahl, J. Hempel, and B.-C. Wang. 1997. The first structure of an aldehyde dehydrogenase reveals novel interactions between NAD and the Rossmann fold. Nat. Struct. Biol. 4:317-326[Medline]. |
| 19. |
Lowry, O. H.,
N. J. Rosebrough,
A. L. Farr, and R. J. Randall.
1951.
Protein measurement with the Folin phenol reagent.
J. Biol. Chem.
193:265-275 |
| 20. | MacKintosh, R. W., and C. A. Fewson. 1988. Benzyl alcohol dehydrogenase and benzaldehyde dehydrogenase II from Acinetobacter calcoaceticus. Biochem. J. 250:743-751[Medline]. |
| 21. |
Miyauchi, K.,
R. Masaki,
S. Taketani,
A. Yamamoto,
M. Akayama, and Y. Tashiro.
1991.
Molecular cloning, sequencing, and expression of cDNA for rat liver microsomal aldehyde dehydrogenase.
J. Biol. Chem.
266:19536-19542 |
| 22. | Niegemann, E., A. Schulz, and K. Bartsch. 1993. Molecular organization of the Escherichia coli gab cluster: nucleotide sequence of the structural genes gabD and gabP and expression of the GABA permease gene. Arch. Microbiol. 160:454-460[Medline]. |
| 23. | Overhage, J., H. Priefert, A. U. Kresse, H. Sommer, G. Krammer, J. Rabenhorst, and A. Steinbüchel. Unpublished results. |
| 24. |
Priefert, H.,
S. Hein,
N. Krüger,
K. Zeh,
B. Schmidt, and A. Steinbüchel.
1991.
Identification and molecular characterization of the Alcaligenes eutrophus H16 aco operon genes involved in acetoin catabolism.
J. Bacteriol.
173:4056-4071 |
| 25. |
Priefert, H.,
N. Krüger,
D. Jendrossek,
B. Schmidt, and A. Steinbüchel.
1992.
Identification and molecular characterization of the gene coding for acetaldehyde dehydrogenase II (acoD) of Alcaligenes eutrophus.
J. Bacteriol.
174:899-907 |
| 26. |
Priefert, H.,
J. Rabenhorst, and A. Steinbüchel.
1997.
Molecular characterization of genes of Pseudomonas sp. strain HR199 involved in bioconversion of vanillin to protocatechuate.
J. Bacteriol.
179:2595-2607 |
| 27. | Rabenhorst, J. 1996. Production of methoxyphenol type natural aroma chemicals by biotransformation of eugenol with a new Pseudomonas sp. Appl. Microbiol. Biotechnol. 46:470-474. |
| 28. |
Saigal, D.,
S. J. Cunningham,
J. Farrés, and H. Weiner.
1991.
Molecular cloning of the mitochondrial aldehyde dehydrogenase gene of Saccharomyces cerevisiae by genetic complementation.
J. Bacteriol.
173:3199-3208 |
| 29. | Sambrook, J., E. F. Fritsch, and T. Maniatis. 1989. Molecular cloning: a laboratory manual, 2nd ed. Cold Spring Harbor Laboratory, Cold Spring Harbor, N.Y. |
| 30. | Schlegel, H. G., H. Kaltwasser, and G. Gottschalk. 1961. Ein Submersverfahren zur Kultur wasserstoffoxidierender Bakterien: Wachstumsphysiologische Untersuchungen. Arch. Mikrobiol. 38:209-222[Medline]. |
| 31. |
Sheikh, S.,
L. Ni,
T. D. Hurley, and H. Weiner.
1997.
The potential roles of the conserved amino acids in human liver mitochondrial aldehyde dehydrogenase.
J. Biol. Chem.
272:18817-18822 |
| 32. | Simon, R., U. Priefer, and A. Pühler. 1983. A broad host range mobilization system for in vivo genetic engineering: transposon mutagenesis in gram-negative bacteria. Bio/Technology 1:784-791. |
| 33. | Steinmetz, C. G., P.-G. Xie, H. Weiner, and T. D. Hurley. 1997. Structure of mitochondrial aldehyde dehydrogenase: the genetic component of ethanol aversion. Structure 5:701-711[Medline]. |
| 34. | Strauss, E. C., J. A. Kobori, G. Siu, and L. E. Hood. 1986. Specific-primer-directed DNA sequencing. Anal. Biochem. 154:353-360[Medline]. |
| 35. | Tadasa, K. 1977. Degradation of eugenol by a microorganism. Agric. Biol. Chem. 41:925-929. |
| 36. | Tadasa, K., and H. Kayahara. 1983. Initial steps of eugenol degradation pathway of a microorganism. Agric. Biol. Chem. 47:2639-2640. |
| 37. | Tinoco, I., P. N. Borer, B. Dengler, M. D. Levine, O. C. Uhlenbeck, D. M. Crothers, and J. Gralla. 1973. Improved estimation of secondary structure in ribonucleic acids. Nat. New Biol. 246:40-41[Medline]. |
| 38. | Wang, X. P., and H. Weiner. 1995. Involvement of glutamate 268 in the active site of human liver mitochondrial (class 2) aldehyde dehydrogenase as probed by site-directed mutagenesis. Biochemistry 34:237-243[Medline]. |
This article has been cited by other articles:
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Copyright © 2009 by the American Society for Microbiology. For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»