Aspartate-beta-semialdehyde dehydrogenase from Escherichia coli. Affinity labeling with the substrate analogue L-2-amino-4-oxo-5-chloropentanoic acid: an example of half-site reactivity.
The substrate binding site of aspartate-beta-semialdehyde dehydrogenase from Escherichia coli was studied by affinity labeling with L-2-amino-4-oxo-5-chloropentanoic acid. The substrate analogue irreversibly inactivates the enzyme with pseudo-first-order kinetics and with a half-of-the-sites reactivity. The substrate aspartate beta-semialdehyde protects the enzyme against the inactivation. A single group is labeled at the active site and is concluded to be the side-chain of a histidine residue. The amino acid sequence around the active site residue was established from a peptic digest of the labeled enzyme: Phe-Val-Gly-Gly-Asp-(modified residue)-Thr-Val-Ser.
D000345:Affinity Labels; D001223:Aspartate-Semialdehyde Dehydrogenase / Q000378:metabolism*; D001665:Binding Sites; D004926:Escherichia coli / Q000201:enzymology*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D007982:Levulinic Acids; D011485:Protein Binding
D000345:Affinity Labels; D007982:Levulinic Acids; C021959:2-amino-4-oxo-5-chloropentanoate; D001223:Aspartate-Semialdehyde Dehydrogenase