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Table 1 Effects of pH on enzyme activity

From: Synthetic metabolic engineering-a novel, simple technology for designing a chimeric metabolic pathway

Buffer pH Specific activity (U mg-1total protein)a Total protein concentration (mg ml-1)b
   GK PGI PFK FBA TIM GAPN iPGM ENO PK MLDH
MES 6 0.19 7.6 4.9 7.3 9.2 0.030 0.11 1.1 9.4 0.0026 8.6
MES 7 3.7 7.3 18 7.3 17 0.039 0.17 2.6 5.2 0.013 2.2
HEPES 7 2.9 2.3 8.8 6.9 13 0.036 0.20 3.1 4.5 0.019 1.7
HEPES 8 5.1 11 18 6.5 5.0 0.042 0.087 1.2 0.65 0.014 2.2
Bicine 8 4.5 16 15 4.0 2.1 0.035 0.078 1.3 1.0 0.011 2.7
Bicine 9 7.5 14 18 2.4 0.07 0.041 0.035 0.66 0.42 0.012 3.0
CHES 9 6.0 14 30 4.4 0.9 0.031 0.017 0.40 0.19 0.0095 4.1
CHES 10 2.6 6.1 10 4.6 2.3 0.0051 0.00075 0.10 0.047 0.0021 41
  1. a The specific enzyme activities in the crude extract of recombinant E. coli were determined under standard assay conditions (50°C) at indicated pHs.
  2. b The total protein concentration of the enzyme mixture (containing 0.01 U each of GK, PGI, PFK, FBA, and TIM, along with 0.02 U each of GAPN, iPGM, ENO, PK and MLDH) was estimated.