Isolation, Purification, Characterization And Modification Of Groups Of Catalase From Aloe

The hydrogen peroxidase is also called catalase(CAT). As one kind of oxidases, catalases can be found in almost all plants, animals and microorganisms. It decomposes hydrogen specifically. As one kind of anti-oxidants, catalse can catalyze Hydrogen peroxide disproportionation reaction. Catalase is one of the key enzymes in the process of evolution of biological defense system. So far it has been widely used in papermaking, textile, food, medicine, environmental protection, etc.Aloe barbadensis Miller is a perennial succulent herbs, classified to Liliaceae. It is a set of viewing, health, beauty, medicine for a pure natural green. Aloe juice is rich in vitamins, amino acids, proteins, polysaccharides, enzymes and trace elements, which in the human body is very useful. We found that Aloe is abundant catalase. As a plant material, the type and content of Aloe protein is less than the animal raw materials and the purification is much simpler. Currently, Aloe catalase purification have not been reported. Aloe leaves was used as raw material in this paper. We studied catalase, For industrial-scale production of catalase provides a reference.The results of our study were followed:1. Purification of catalse from Aloe barbadensis Miller leavesThe catalase was extracted by ammonium sulfate precipitation, and ion-exchange chromatography on DEAE-Sepharose, and ion-exchange chromatography on CM-Sepharose and gel filtration on Sephacryl S-200. SDS-PAGE was used to identify the purity of the catalase. The enzyme was purified to electrophoretic homogeneity. It was purified 228.05-fold and the activity recovery 14.10 percent was obtained. Its specific activity was 17427.30 U/mg.2. Properties of catalaseThe relative molecular weight of this catalase was 239.90 kD, and the weight of subunit was 60.60 kD. The catalase consists of four identical subunits. Studies on the properties of the catalase showed that the optimum temperature was 45℃and the optimum pH was 7.5. The apparent Km of this enzyme was 34 mmol/L. 3. Inhibitors of catalaseAmong several mental ions, Ba2+,K+ can activate the enzyme activity, SDS,oxalic acid,Cu2+ Zn2+ are strongly inhibited the activity, EDTA,KSCN,Fe2+ have little inhibition, Ascorbic,acidurea,Li+,Na+,Mn2+,Ca2+,Mg2+ have little effect on catalase.4. Chemical modification of catalseFunctional group modification that:DTT has a strong inhibitory effect to the catalase,followed by Chloramine-T,BrAc,BD,NAI and Maleic anhydride. While PCMB,PMSF can activate the enzyme activity.