[Some physical and chemical properties of serinesulfhydrase from chicken liver]

An improved procedure of purification of serinesulfhydrase from chicken liver is described. Preparations of enzyme (700-fold purification with the yield of 40 per cent from total activity) have been obtained homogeneous on polyacrylamide gel electrophoresis. Molecular weight of serinesulfhydrase is 90.000; 1 mole of enzyme contains 2 moles of pyridoxalphosphate and consists apparently of 2 subunits. Amino acid composition of the enzyme is studied. Absorption spectrum of serinesulfhydrase has a maximum at 430 nm what is characteristic of numerous pyridoxal-P enzymes. The position of this maximum does not depend on pH (within its range 6--10) and the presence of L-serine, a primary enzyme substrate. An essential change in the absorption spectrum of enzyme was observed in the presence of some thiol compound--DL-homocysteine, beta-mercaptoethanol and glutathione (cosubstrates of the reaction) and L-cysteine (a primary reaction substrate). It is suggested that this change in the spectrum is due to the action of SH-compounds on the enzyme conformation before the beginning of the enzymatic reaction or on its initial stages.