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Inactivation of cytosolic aspartate aminotransferase accompanying modification of Trp 48 by N ‐bromosuccinimide
Author(s) -
Nagashima Fujio,
Tanase Sumio,
Morino Yoshimasa
Publication year - 1986
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(86)80312-x
Subject(s) - n bromosuccinimide , tryptophan , enzyme , chemistry , cytosol , biochemistry , chemical modification , stereochemistry , amino acid , organic chemistry , halogenation
Reaction of N ‐bromosuccinimide with pig heart cytosolic aspartate aminotransferase led to loss of the enzymatic activity. Chemical analysis indicated the modification of two tryptophan residues. At a low ratio of N ‐bromosuccinimide to enzyme, oxidation of Trp 122 occurred without affecting the enzymatic activity. Increase in the ratio resulted in the oxidation of Trp 48 with a concomitant decrease in enzyme activity. The modified enzyme did not react with substrates and their analogs. Trp 48 is not within the active site but in the hinge region linking the large domain of the enzyme to the small domain that shows dynamic movement upon binding substrates. The present result suggests that oxidation of Trp 48 may impair the structural integrity of the interdomain interface.