National Academy of Agricultural Sciences (NAAS)
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PRINT ISSN : 2319-7692 Online ISSN : 2319-7706 Issues : 12 per year Publisher : Excellent Publishers Email : editorijcmas@gmail.com / submit@ijcmas.com Editor-in-chief: Dr.M.Prakash Index Copernicus ICV 2018: 95.39 NAAS RATING 2020: 5.38 |
Cholesterol oxidase (CO) was purified from P. chyrsogenum by 85% ammonium sulphate precipitation, DEAE-Cellulose and Sephadex G-200. The final specific activity was 300 units mg-1 protein and 230-fold. CO was purified to homogeneity as indicated by SDS-PAGE which expressed a single band at 43 KDa. The optimal cholesterol concentration was 1mM. Km and Vmax values were 0.53 %w/v and 51.5 Umg-1 protein, respectively. The optimal incubation time for enzyme catalysis was 15 min. The optimal temperature was 40oC and the optimal pH was 7. At 1 mM and 5mM Ca+2 activated CO whereas Cu+2, mg+2, Hg+2, B+2, and Fe+2 inhibited CO activity. Hg+2 was the most potent inhibitor which abolished 69.1% and 86.8% a t 1 mM and 5 mM, respectively. Ethylenediaminetetra acetate (EDTA), ethyleneglycoltetra acetate (EGTA), 0-phenanthroline and α-α-dipyridyl inhibited CO activity with IC50 of 9.7, 7.6, 20.8 and14.2 mM, respectively indicating that CO is a metalloenzyme. N-ethylmaleimide (NEM), dansyl chloride (DnsCl), N-bromosuccinimide (NBS) and diethylpyrocarbonate (DEPC) and butandione (BD) inhibited CO of from P. chrysogenum in concentration-dependent manner with IC50 values 5.1, 5.8, 6.7, 8.1 and 8.2 mM, respectively indicating the essentiality of sulfhydryl, lysyl, histidyl, tryptophanyl and arginyl groups, respectively.
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