title: Purification and Characterization of a C-S-Lyase from Ramson, the Wild Garlic,Allium ursinum.
abstract: A C-S-lyase preparation from ramson, ALLIUM URSINUM L., has been purified to apparent homogeneity. Separation techniques applied were hydrophobic interaction chromatography, anion exchange chromatography, and gel permeation chromatography. A 52-fold purification was obtained. The enzyme could be characterized by a molecular mass of M (r) = 150000 with subunits of 50 000. Its isoelectric point was determined to be at 4.7. The pH-optimum for the substrate-dependent turnover was found at 6.0. The temperature optimum was at 35 degrees C. (+)-Alliin as the substrate caused the highest enzymatic reaction velocity. The lowest K (m) value was observed with (+)- S-propyl- L-cysteine sulfoxide. Inhibitor constants were elaborated for the deoxy-derivatives of the substrates inserted and, likewise, for related amino acids. The protein was sensitive to low concentrations of hydroxylamine, indicating pyridoxal phosphate as a cofactor. Activation energies were determined for the cleavage of alliin, S-propyl- L-cysteine sulfoxide and S-methyl- L-cysteine sulfoxide, and were found to be in the range of 9 to 13 kJ . mol (-1).
authors.affiliation: Institut für Botanik und Pharmazeutische Biologie der Universität Erlangen-Nürnberg, Staudtstraße 5, 91058 Erlangen, Federal Republic of Germany.
authors.forename: J
authors.initials: J
authors.lastname: Landshuter
authors.forename: E M
authors.initials: EM
authors.lastname: Lohmüller
authors.forename: K
authors.initials: K
authors.lastname: Knobloch