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Table 2 In vitro activities of various enzymes involved in n-butanol production pathways expressed in S. cerevisiae

From: n-Butanol production in Saccharomyces cerevisiae is limited by the availability of coenzyme A and cytosolic acetyl-CoA

Enzyme Activity [U/mg] high copy vector Activity [U/mg] low copy vector
Thiolase
 Sc ERG10 0.043 ± 0.009 0.10 ± 0.005
 Ca thlA 0.15 ± 0.04 4.96 ± 0.4
 None 0.003 ± 0.0003 0.004 ± 0.002
Acetyl-CoA:malonyl-CoA acyltransferase
 Ss nphT7 NM 0.12 ± 0.009
 None NM 0.002 ± 0.001
3-Hydroxybutyryl-CoA DH
Ca hbd 0.31 ± 0.04 1.47 ± 0.19
 None 0.011 ± 0.004 0.063 ± 0.01
Crotonase
 Ca crt 3.5 ± 1.07 35.64 ± 3.2
 None 0.17 ± 0.04 4.09 ± 2.2
Trans-2-enoyl-CoA reductase
 Eg ter ND 0.002 ± 0.001
 Td ter ND 0.0103 ± 0.002
 None ND ND
Crotonyl-CoA reductase
 Sco ccr NM 0.001 ± 0.00009
 None NM ND
Butyraldehyde-DH
 Ca adhE2 (pVS1) 0.00027 ± 0.00002 0.0039 ± 0.003
 Ca adhE2 + Ec eutE (pVS6) 0.00091 ± 0.0004 0.06 ± 0.009
 Ec eutE 0.014 ± 0.0083 0.044 ± 0.004
 None ND 0.0022 ± 0.0009
Butanol-DH
 Ca adhE2 (pVS1) 0.07 ± 0.02 0.062 ± 0.015
 Ca adhE2 (pVS6) 0.053 ± 0.02 0.076 ± 0.005
 Ca bdhB 0.073 ± 0.03 0.044 ± 0.008
 None 0.049 ± 0.01 0.04 ± 0.009
  1. The mean values of three independent replicates are shown with standard deviations. One unit (U) is defined as the conversion of 1 µmol of substrate into the corresponding product per 1 min. The term “none” refers to the empty vector control, which means for the high copy variants (2 µ) pRS62K and for the low copy variants (CEN6/ARS4) pRS41K. Genes from Saccharomyces cerevisiae (Sc), Clostridium acetobutylicum (Ca), E.coli (Ec), Euglena gracilis (Eg), Streptomyces collinus (Sco), Streptomyces sp. CL190 (Ss), and Treponema denticola (Td) are indicated by prefixes in superscript
  2. ND not detectable, NM not measured