High Performance Liquid Chromatography Determination of Cystathionase Activity in Human and Rabbit Lenses

Abstract
Cystathionase activity has been demonstrated in human and rabbit lenses, using L-homoserine as substrate. The amount of activity found was quite low, 0.05 and 0.08 nmol of α-ketobutyrate formed/h/mg protein in human and rabbit lenses, respectively. The human lens cystathionase was found to have a pH maximum of 8.5 and a Km of 23.8 mM for L-homoserine. A sensitive assay, involving the use of high performance liquid chromatography, was developed to measure the small amounts of α-ketobutyrate produced.