Michaelis-constants and enzyme activities for dehydrogenation and transamination of the three branched chain alpha-keto acids in liver, kidney, skeletal muscle, and brain of rats are reported. After ...oral load only 11-22% of the keto acids pass the liver unchanged. Blood levels in pharmacokinetic and absorption studies are related to the Michaelis-constants. At the low keto-acid concentrations after oral application, dehydrogenation in the non-hepatic tissues is supposed to prevail over transamination. Data on feed efficiency of branched chain alpha-keto acids reported in the literature support this view. The chance for transamination is better after intravenous administration. The transferability of our data to humans, and various factors influencing the efficiency of branched chain alpha-keto acids are discussed in connection with data reported in the literature.
Transamination in green plants RAUTANEN, N
Journal of biological chemistry/The Journal of biological chemistry,
06/1946, Letnik:
163, Številka:
3
Journal Article
Arachidonic acid (5 microM), prostaglandin E2 (0.28 microM) and F2 alpha (14 microM) inhibited (P less than 0.01) the rates of net leucine transamination, leucine oxidative decarboxylation and total ...CO2 production from leucine in extensor digitorum communis muscles from fed ten-day-old chicks. Indomethacin (50 microM) markedly inhibited (P less than 0.01) the rate of PGE2 production in the presence of 5 microM arachidonic acid and prevented the inhibition of leucine degradation by arachidonic acid in skeletal muscle. These results demonstrate that the actions of arachidonic acid on leucine degradation in chick skeletal muscle are mediated by metabolites generated via the cyclooxygenase pathway and that prostaglandins may play a role in the regulation of leucine degradation in skeletal muscle.
Tris(N,N-dialkylamino)phosphines undergo a transamination reaction with N-(O-alkyl-O-allyl-thio-phosphoryl)-N′-benzoylureas. Eight new compounds were synthesized by this method and characterized by ...IR,
1
H NMR and
31
P NMR.
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