Abstract
Comparison of the Catalytic Competence of Different Animal Hepatic Microsomal Fractions Prepared by Calcium Aggregation and Differential Centrifugation Methods
Department of Pharmaceutical Chemistry, Bombay College of Pharmacy, Kalina, Santacruz (E), Mumbai 400098, India
Correspondence Address:
K. R. Iyer, Department of Pharmaceutical Chemistry, Bombay College of Pharmacy, Kalina, Santacruz (E), Mumbai 400098, India, E-mail: krishna.iyer@bcp.edu.in
Rat, mouse, guinea pig and rabbit liver microsomes were prepared by both conventional differential centrifugation (ultracentrifugation) method and calcium aggregation method. The isolated microsomes were compared in terms of their spectral cytochrome P450 content, protein content, specific spectral cytochrome P450 content and cytochrome P450 family 2 subfamily E member 1 catalytic activity. The specific spectral cytochrome P450 content (nmol/mg protein) was generally higher in microsomes isolated by the calcium aggregation method. Likewise, the catalytic activity expressed as nmol of p-nitrocatechol formed/min/ mg protein was also higher in microsomes isolated by calcium aggregation. However, the catalytic activity expressed as nmol of p-nitrocatechol formed/min/nmol cytochrome P450 was statistically different (less) only is mouse microsomes isolated by calcium aggregation. Overall, the two microsome isolation methods were comparable with ultracentrifugation appearing to yield more catalytically incompetent protein than calcium aggregation.
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