type	Journal Article
authors	Tomisawa, H.; Ichihara, S.; Fukazawa, H.; Ichimoto, N.; Tateishi, M.; Yamamoto, I.
title	Purification and characterization of human hepatic cysteine-conjugate beta-lyase
journal	Biochem J
Activity	4.4.1.13
ui	86295644
year	(1986)
volume	235
number	2
pages	569-75.
keywords	Chromatography, Gel
abstract	Cysteine-conjugate beta-lyase (EC 4.4.1.13) was purified about 880-fold from human liver obtained post mortem. The purification procedure included (NH4)2SO4 precipitation, chromatography on DEAE-cellulose and hydroxyapatite, gel filtration on Sephadex G-200, and chromatofocusing. The purified enzyme cleaves the C-S bond of several S-aryl-L-cysteines to yield equimolar amounts of thiols, pyruvic acid and ammonia via an alpha beta-elimination reaction. The Mr of the enzyme was estimated to be 88,000 by gel filtration. The enzyme is thermolabile, has a pH optimum of 8.5, and an apparent Km of 0.7 mM towards S-(p-bromophenyl)- L-cysteine. The enzyme requires pyridoxal 5'-phosphate as a cofactor, and hence the enzyme activity was completely abolished by hydroxylamine. No effect of EDTA or thiol-blocking reagents was observed on the activity of the enzyme.
last changed	2002/11/12 16:17