Isolation,Purification and Some Characterization of Catalase from Garlic Seedlings

Electrophoresis-purity catalase from fresh garlic seedlings was obtained through homogenization,buffer solution extraction,ammonium sulfate precipitation,DEAE-Sepharose ion exchange chromatography and Superdex-200 gel filtration chromatography.The specific activity of purified CAT was 25975.36 U/mg with a recovery of 40.05% and a purification factor of 125.97.The molecular and subunit molecular weight of this enzyme was 234.93 kD and 59.16 kD,respectively.It was relatively stable in the range of 25—45 ℃ and pH 5.0—10.0 Its optimum temperature and pH were 45 ℃ and 7.2,respectively.Furthermore,its Km was 38.2 mmol/L under the optimum conditions.Its activity was inhibited by methanol,ethanol,isopropanol,SDS and KSCN as well as some metal ions such as Ag+,Cu2+,Mn2+,Co2+,Cd2+,Zn2+,Ca2+,Mg2+ and Ba2+,but was activated by Li+and Pb2+as well as low concentration of K+.