Purification of α-galactosidase from coconut endosperm by affinity chromatography

Four specific adsorbants for the purification of α-galactosidase (α -D galactoside galactohydrolase EC 3.2 1.22) from coconut endosperm were prepared. The affinity gels prepared were Sepharose-4B-lysine-galacturonate, Sepharose-4B-lysinegalactosamine, Sepharose-4B-lysine-galactose-p-carboxyaniid and CH-Sepharose- 4B-galactosamine. α -Galactosidase from coconut endosperm extract was partially purified by ammonium sulphate fractionation, DEAE-Sephadex chromatography and this partially purified preparation was further purified by affinity chromatography using these specific adsorbants. The adsorbed α -galactosidase was eluted either by using a linear gradient of increasing buffer concentration or by using the specific desorbant p-nitrophenyl- α -D-galactopyranoside. The specific activity of the purified enzyme tested with p-nitrophenyl- α -D-galactopyranoside as substrate was 20 units/mg protein. This represents a 900 fold increase in purification of the original crude extract and the yield was 67%. The purified enzyme was homogeneous by polyacrylamide gel electrophoresis.