title: Principles of enzyme stabilization. V. The possibility of enzyme selfstabilization under the action of potentially reversible intramolecular cross-linkages of different length.
abstract: The denaturing action of guanidine . HCl on modified alpha-chymotrypsin (EC 3.4.21.1) preparations has been studied. The consecutive treatment of alpha-chymotrypsin with N-acetyl-homocysteine thiolactone, 5,5'-dithio-bis-(2-nitrobenzoic acid) and dithiols of HS-(CH2)n-SH type, with n ranging from 4 to 10, leads to enzyme stabilization as a result of protein modification. A greater stabilization effect can be achieved by enriching the protein molecule with groups reactive towards dithiols, after first modifying carboxygroups. In this case dithiol with n=5 forms an intramolecular cross-linkage. If an equimolecular mixture of different dithiols is used for enzyme modification, the enzyme gradually 'selects' 1,5-dithiol for the formation of an intramolecular cross-linkage instead of the initial one-point modification. The use of potentially reversible cross-linkages may be generally employed for the preparation of stabilized water-soluble enzymes via the mechanism of selfstabilization.
mesh_terms: D002918:Chymotrypsin / Q000378:metabolism; D004355:Drug Stability; D004789:Enzyme Activation; D005029:Ethylenediamines / Q000494:pharmacology; D007700:Kinetics; D046911:Macromolecular Substances; D011485:Protein Binding; D011487:Protein Conformation; D013329:Structure-Activity Relationship; D013438:Sulfhydryl Compounds / Q000494:pharmacology
chemical_list: D005029:Ethylenediamines; D046911:Macromolecular Substances; D013438:Sulfhydryl Compounds; D002918:Chymotrypsin