Abstract

Cysteine desulfhydrase (EC 4, 4, 1. 1. ) was purified from the culture supernatant of Streptomyces albidoflavus SMF301 by hydroxyapatite, gel filtration and Resource Q ion-exchange chromatography with a purification fold of six identical subunits. The enzyme was stabilized by dithiothreitol and pyridoxal 5'-phosphate during the purification procedures. The optimum pH and temperature were pH 8.6 and 35℃, respectively. The N-terminal amino acid sequence was identified as A-P-L-P-T-A-D-V-R-S-D-P-G-Y-E-W-L-G-E-A-V. The purified cystein desulfhydrase had a high substrate specificity toward cysteine, and exhibited no cystahionine λ-lyase activity. The K_m value for cysteine was determined to be 0.37 mM.

• Keywords: Cysteine desulfhydrase; Streptomyces; purification; N-terminal sequence