Abstract
Papain (EC 3.4.4.10) is a proteolytic enzyme which is isolated from the Papaya, a common tropical tree. It is a sulphydryl enzyme and its SH group is required for enzymic activity. Papain as usually prepared (Kimmel & Smith 1954) contains only a small portion of active molecules. The majority of the molecules are inactive because their sulphydryl group is blocked. Part of the blocking is caused by disulphide formation with cysteine (Sluyterman 1967). This disulphide can be reduced by an excess of cysteine resulting in an active enzyme preparation. The free SH content never reaches 100% and is often not more than about 50% , so that we must distinguish between papain molecules with a reversibly and an irreversibly blocked SH group. The chemical nature of the irreversible blocking is not yet known. It might well be due to a higher oxidation state of the sulphur which cannot be reduced by an excess of cysteine (Glazer & Smith 1965).
Subject
Industrial and Manufacturing Engineering,General Agricultural and Biological Sciences,General Business, Management and Accounting,Materials Science (miscellaneous),Business and International Management
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69 articles.
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