A-Ketoglutaramic acid

Studies on the transamination of glutamine with a-ketoacids (127-132) have shown that a-ketoglutaramic acid is formed as a product. a-Ketoglutaramic acid has been found to exist in solution in equilibrium with the cyclic ketolactam form ... 

Transamination with Glutamine and Asparagine. Meister and collaborators have described two types of transaminase in which the amino donor is glutamine or asparagine. Transamination from glutamine to any of more than 30 a-keto acids leads to the formation of a-ketoglutaramic acid, which is hydrolyzed by a specific amidase (HI). The reaction... 

Glutamine (and probably asparagine) can be destroyed by two independent routes. The enzyme catalysing direct deamidation to glutamate is activated by phosphate, suggesting a mechanism related to that of glutamine synthetase. The second path involves transamination (equation 30) and subsequent deamidation (equation 31) of a-ketoglutaramic acid. The two reactions are catalysed by separate... 

A second type of deamidation reaction for glutamine and asparagine exists. Early work by Greenstein and co-workers demonstrated the existence of an a-keto acid-activated glutaminase and aspart nase in liver 43). It was own later by Meister and associates ( 44, 4 ) that these enzymes catalyze a transamination reaction between the amino acid amides and a-keto acids followed by the hydrolysis of the a-ketoglutaramic or a-ketosuccinamic acids with the release of ammoiua. These reactions will be considered in Section IV, 2. 

Extracts of a number of tissues catalyze the hydrolysis of the a-keto acid-(o-amides (a-ketoglutaramic and a-ketosuccinamic acids). The enzyme has been partially purified from rat liver 256, 270, 271). 

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