title: Thiol and amino analogues as alternate substrates for glycerokinase from Candida mycoderma.
abstract: The kinetic and catalytic mechanism of glycerokinase from Candida mycoderma was examined with thiol and amino analogues of glycerol and with MgAMPPCP, an analogue of MgATP. (S)-1-Aminopropanediol was phosphorylated on nitrogen (Vmax 0.4% that of glycerol) while the R enantiomer was phosphorylated on oxygen (Vmax 0.7% that of glycerol). (S)-1-Mercaptopropanediol was phosphorylated on oxygen (Vmax 3.5% that of glycerol), while the R enantiomer was phosphorylated on sulfur (Vmax 0.001% that of glycerol). The hydroxyl group at C-2 thus orients the substrate in the active site, while that at the carbon remote from phosphorylation enhances both catalysis and binding of the substrate, presumably because of hydrogen-bonding interactions. The kinetic mechanism is random with a high degree of synergistic binding between the substrates, so that the mechanism appears ordered with glycerol adding first but equilibrium ordered with MgATP binding first with the amino analogues.
authors.affiliation: Institute for Enzyme Research, University of Wisconsin, Madison 53706.
authors.forename: W B
authors.initials: WB
authors.lastname: Knight
authors.forename: W W
authors.initials: WW
authors.lastname: Cleland
mesh_terms: D000255:Adenosine Triphosphate; D000588:Amines; D001665:Binding Sites; D002175:Candida / Q000201:enzymology*; D004926:Escherichia coli / Q000201:enzymology; D005991:Glycerol Kinase / Q000378:metabolism*; D007700:Kinetics; D010766:Phosphorylation; D010770:Phosphotransferases / Q000378:metabolism*; D013379:Substrate Specificity; D013438:Sulfhydryl Compounds
chemical_list: D000588:Amines; D013438:Sulfhydryl Compounds; D000255:Adenosine Triphosphate; D010770:Phosphotransferases; D005991:Glycerol Kinase