TABLE 1

Amino acid compositions determined by Raman spectroscopy and UPLC and as reported in the literature

Amino acidOptimum Raman band (cm−1)Amino acid composition (%) based on:
Raman spectroscopyUPLCPublished valueb
Ala1,30811.111.19.60
Arg1,1992.463.395.53
Asp/Asn1,6956.418.989.01
Cys6781.241.64a1.64
Glu/Gln1,31910.89.169.84
Gly1,33211.312.011.5
His7312.160.8901.77
Ile1,30911.18.765.43
Leu1,2439.6711.48.42
Lys1,0723.445.246.41
Met7651.140.4672.87
Phe1,2145.784.593.46
Pro8430.7271.024.13
Ser1,0104.374.424.03
Thr1,1163.386.264.74
Trp7591.411.06a1.06
Tyr7981.700.3902.58
Val1,45411.79.227.91
Sum100100100
  • a Values for Cys and Trp could not be resolved by the UPLC method. Cys is converted to several oxidation products, while Trp is destroyed during the acidic protein hydrolysis method used in this research. The published literature values were used for Cys and Trp.

  • b Amino acid composition is defined as the fraction of each amino acid among E. coli total protein. The published values were obtained from reference 55.