Liver, cocarboxylase

Some coenzyme measurements have been reported which should be related to the changes in enzyme activities. Scurvy decreased liver cocarboxylase concentration by half (B20) but did not alter pyridine nucleotide coenzymes (Bll). Rats fed extra ascorbic acid (100 mg/day) had a decreased liver coenzyme A content of about 40 % after three days (C2). 

Biotin (8.49), a thiophene-lactam, occurs in yeast, liver, kidney, eggs, vegetables, and nuts. It functions as a cocarboxylase in a number of biochemical reactions. It binds COj in the form of an unstable carbamic acid on one of the lactam nitrogens. The carbamate carboxyl is then donated easily. 

Following absorption, thiamin is transported to the liver where it is phosphorylated under the action of ATP to form the coenzyme thiamin diphosphate (formerly called thiamin pyrophosphate or cocarboxylase), (see Fig. T-9) although this phosphorylation occurs rapidly in the liver, it is noteworthy that all nucleated cells appear to be capable of bringing about this conversion. 

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