Deuterium isotope effect in the transamination of p-tyrosine by rat liver tyrosine transaminase.
The rate of transamination of p-tyrosine catalyzed by rat liver soluble tyrosine aminotransferase (E.C. 2.6.1.5.) was significantly reduced when the hydrogen at the alpha-carbon position is replaced by deuterium or when the reactions were conducted in 2H2O. The cleavage of carbon-hydrogen bond at alpha-carbon position is at least partly involved in the rate-limiting step of tyrosine transamination. In 2H2O solvent the reduction of the overall rates of transamination of both p-tyrosine and alpha-2H1-p-tyrosine occurred uncompetitively which suggests that the deuterium solvent effect is involved in the tautomerization of the external Schiff's base.
Yu
P H
PH
Nguyen
T V
TV
D000818:Animals; D055598:Chemical Phenomena; D002621:Chemistry; D003903:Deuterium / Q000494:pharmacology*; D007656:Ketoglutaric Acids / Q000378:metabolism; D007700:Kinetics; D008099:Liver / Q000201:enzymology*; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D014443:Tyrosine / Q000378:metabolism*; D014444:Tyrosine Transaminase / Q000378:metabolism*
D007656:Ketoglutaric Acids; D014443:Tyrosine; D003903:Deuterium; D014444:Tyrosine Transaminase