Pyridoxin deficiency in the rat; liver L-cysteic acid decarboxylase activity and urinary amino-acids.

A recent survey of the urinary amino-acids of various animals (Datta & Harris, 1951, 1953) has shown taurine to be present in the urine of some species, e.g. the mouse, rat and dog, but absent from others, e.g. the guinea-pig, cow and rabbit; the occurrence of taurine in cat's urine is irregular. Some time ago an enzyme was described that liberates carbon dioxide from L-cysteic acid under anaerobic conditions (Blaschko, 1942). This enzyme occurs in the liver of the dog and the rat, but it has not been found in some other species, e.g. the cat. The product of the decarboxylation had not been identified, but the amount of carbon dioxide formed-one mole of CO, for one mole of L-cysteic acid addedsuggested that it was taurine: