Regulation of serine racemase activity by amino acids.
The effects of various amino acids on the activity of serine racemase, purified from mouse brain, were examined. Those acting as inhibitors included compounds with electron withdrawing groups on the beta-carbon of alanine (beta-halo-alanines and L-serine-O-sulfate), which can act as enzyme-activated inhibitors, and compounds containing beta-SH groups (cysteine and homocysteine) which react with enzyme-bound pyridoxal phosphate to form thiazolidine derivatives. Glycine and a series of metabolites related to L-aspartic acid (L-aspartic acid, L-asparagine, and oxaloacetic acid) were also found to be competitive inhibitors of the racemase. The Ki values for glycine and aspartic acid inhibition were 0.15 and 1.9 mM, respectively, indicating that alterations in the concentrations of these amino acids might play a role in the regulation of D-serine synthesis.
Dunlop
David S
DS
Nathan Kline Institute for Psychiatric Research, 140 Old Orangeburg Road, Orangeburg, NY 10962, USA. Dunlop@nki.rfmh.org
Neidle
Amos
A
D000255:Adenosine Triphosphate / Q000494:pharmacology; D000596:Amino Acids / Q000494:pharmacology*; D000818:Animals; D001921:Brain / Q000187:drug effects / Q000201:enzymology; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation / Q000187:drug effects*; D051379:Mice; D008810:Mice, Inbred C57BL; D019289:Pyruvic Acid / Q000378:metabolism; D019998:Racemases and Epimerases / Q000187:drug effects* / Q000378:metabolism*; D012694:Serine / Q000378:metabolism; D013997:Time Factors; D000099300:Serine Racemase
D000255:Adenosine Triphosphate; D000596:Amino Acids; D019289:Pyruvic Acid; D019998:Racemases and Epimerases; D012694:Serine; D000099300:Serine Racemase