Abstract
The O-acetyl-L-serine sulfhydrylase (EC 4.2.99.8) from Chlamydomonas reinhardtii has been immobilized either by ionic binding to DEAE-cellulose or by covalent bonding to alkylamine silica and to vinyl acetate-divinylethylene urea copolymers. The immobilized enzyme had improved stability and showed sigmoidal kinetic behaviour with respect to O-acetyl-L-serine, but without major alterations in the corresponding apparent Km value or in the inhibitory effects of this substrate observed with the enzyme in solution. In addition, significant changes in optimum pH and reaction temperature for O-acetyl-L-serine sulfhydrylase activity were observed.