Preliminary Studies on the Amino-acid Residues at Active Center of the Lysozyme from Raphanus sativus Leaves.
A 1ysozyme from Raphanus sativus leaves was purified by the method of affinity chromatography on a deaminated regenerated crab chitin column. The purified enzyme was crystallized and showed a single band on polyacrylamide gel disc electrophoresis. The functional groups at the active center of the enzyme were studied by the method of pH dynamics and chemical modification. It was found that carboxyl groups(Glu/Asp), tryptophanyl and histidyl residues were probably essential groups for the catalytic activity. The enzymatic activity was not affected when the enzyme was modified by reagents which could specifically react with tyrosyl, cysteinyl, arginyl and seryl/threonyl residues. It was inhibited by histamine and GlcNAc. The difference among Raphanus sativus lysozyme, HEWI and papaya lysozyme was discussed.
Yi
Ji-Cai
JC
College of Biotechnology, South China Agricultural University, Guangzhou 510642, China.
Xu
Feng-Cai
FC