Alanine sulfodisulfane

This chapter discusses the determination of alanine sulfodisulfane or cysteine thiosulfonate. Synthesis of alanine sulfodisulfane from cystine disulfoxide and thiosulfate; and cystine and thiosulfate is described. The identification and quantitative determination of alanine sulfodisulfane in tissue extracts can be achieved with a dual column procedure. Paper electrophoresis successfully separates alanine sulfodisulfane from related amino acids. Using a Savant Instruments high voltage electrophoresis apparatus at 4500 V for 120 min, a formic acid-acetic acid buffer at pH 1.9 (240 ml of formic acid and 960 ml of acetic acid made to a volume of 12 liters with distilled water) is employed. Alanine sulfodisulfane can be cleaved with reducing agents, such as dithiothreitol to yield cysteine and thiosulfate. Zinc and hydrochloric acid reduce the amino acid to cysteine, hydrogen sulfide, and sulfite. Oxidation of alanine suffodisulfane with hydrogen peroxide yields cysteic acid. Rat liver homogenates produce substantial amounts of alanine sulfodisulfane when incubated with cystine.