Alanine and Taurine Formation from Injected Cysteine in the Rat

Abstract

THE pathways for cysteine metabolism have been studied intensively, and a great deal is known about the many reactions which lead to the formation of sulphate. Most of the studies on cysteine have been mainly concerned with the fate of sulphur; but relatively few experimental results exist concerning the fate of the carbon chain. Recently, Fromageot and Chatagner¹ have furnished proof of the existence of an enzyme, desulphinicase, in liver of rabbits. This enzyme is capable of liberating sulphurous acid from L-cysteine sulphinic acid. They considered the latter compound to be the most important intermediate in the conversion of organic sulphur to inorganic sulphur; they assumed that the splitting of sulphurous acid from L-cysteine sulphuric acid gave alanine as an intermediate. The formation of alanine from cysteine sulphinic acid has been demonstrated in rabbit liver extracts².