作者: J R LaDine , D Carlow , W T Lee , R L Cross , T G Flynn
DOI: 10.1016/S0021-9258(19)67631-3
关键词: Biochemistry 、 Pyridoxal 、 Affinity label 、 Dehydrogenase 、 Leuconostoc mesenteroides 、 Enzyme 、 Affinity labeling 、 Chemistry 、 NAD+ kinase 、 Pyridoxal phosphate
摘要: Pyridoxal 5'-diphospho-5'-adenosine (PLP-AMP) inhibits glucose-6-phosphate dehydrogenase from Leuconostoc mesenteroides competitively with respect to glucose 6-phosphate and noncompetitively NAD+ or NADP+, Ki = 40 microM in the NADP-linked 34 NAD-linked reaction. Incubation of [3H]PLP-AMP followed by borohydride reduction shows that incorporation 0.85 mol PLP-AMP per enzyme subunit is required for complete inactivation. Both protect against this covalent modification. The proteolysis modified isolation sequencing labeled peptides revealed Lys-21 Lys-343 are sites interaction both lysyl residues 5'-phosphate (PLP) also modifies probably Lys-343. part a highly conserved region present all dehydrogenases have been sequenced. corresponds an arginyl residue other less homologous those enzymes. PLP believed interact L. at binding site. Simultaneous induces conformational changes (Kurlandsky, S. B., Hilburger, A. C., Levy, H. R. (1988) Arch. Biochem. Biophys. 264, 93-102) postulated interfere Schiff's-base formation PLP-AMP. One covalently may be located regions undergoing NAD(+)-induced changes.