Table 1.

G3PDH-specific activity of the parent strain and mutant strains deficient in the synthesis of glycerol kinase or G3PDH subunit A homologs

Straina1G3PDH sp act (mU·mg−1)bwith the following medium:
Gly MMGlu MMGly Glu MM
H26 (parent)76 ± 1028 ± 467 ± 10
ΔglpA1mutantNo growth19 ± 118 ± 1
ΔglpA2mutant55 ± 624 ± 247 ± 6
ΔglpA1ΔglpA2mutantNo growthUDUD
ΔglpKmutantNo growth19 ± 421 ± 1
ΔglpA1/glpA1strain70 ± 926 ± 668 ± 9
ΔglpA1/glpA2strain67 ± 328 ± 567 ± 4
ΔglpA2/glpA2strain73 ± 928 ± 572 ± 7
ΔglpK/glpKstrain72 ± 827 ± 367 ± 5
  • a The ΔglpKstrain is deficient in the synthesis of glycerol kinase; the ΔglpA1and ΔglpA2strains are deficient in the synthesis of G3PDH subunit A homologs. Slashes are used to indicate strains with plasmids expressing glpK, glpA1, or glpA2in trans.

  • b G3PDH activity was determined for cell lysates as described in Materials and Methods. Cells were grown to log phase in minimal medium (MM) with Gly, Glu, or both as indicated. No growth, mutant strains that did not grow on Gly MM; UD, undetectable levels of activity. Experiments were performed in biological triplicate, and the means ± standard deviations were calculated. No activity was detected for controls with no substrate or with boiled cell lysates.