Table 3.
Amino acid substitution in HII:E423–442 | vi/vo |
---|---|
None | 0.50 |
S423A | 0.50 |
G427D | 1.12 |
T428V | 0.38 |
R429N | 0.22 |
E434V | 0.52 |
R436K | 0.46 |
Glycerol kinase activity in crude cellular extracts was determined in duplicate without and with 10 μM IIAGlc added to the assay and corrected for glycerol-independent background rates. IIAGlc inhibition is expressed as the ratio of the reaction velocity with IIAGlc, vi, to the velocity without IIAGlc, vo. Duplicate values for vi/vo differed from the reported average value by 0.01 or less.
Amino acid substitutions in this chimeric enzyme are shown by using the single-letter abbreviations and sequence number, where the amino acid replacement is the residue in HiGK.
Determination of the IIAGlc concentration dependence of inhibition for the HII:E423–442 parent enzyme yielded K50 = 3 ± 0.2 μM and Imax = 65 ± 1%.