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Hydralazine binds covalently to complement component C4
Author(s) -
Sim Edith,
Law Sai-Kit A.
Publication year - 1985
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(85)80631-1
Subject(s) - complement (music) , chemistry , hydralazine , covalent bond , component (thermodynamics) , pharmacology , biochemistry , medicine , blood pressure , organic chemistry , gene , physics , complementation , phenotype , thermodynamics
Long‐term treatment with hydralazine is sometimes associated with deposition of immune complexes and development of systemic lupus erythematosus (SLE) as an adverse side‐effect. Hydralazine inhibits the covalent binding reaction of the complement protein C4. We show that when hydralazine inhibits C4, it becomes covalently bound to the polypeptide chain containing the active site thiol ester. C4 is encoded at 2 adjacent polymorphic loci, C4A and C4B, within the major histocompatibility complex. We show that hydralazine binds more efficiently to the C4A than to the C4B gene product and suggest that C4 type may predispose patients to hydralazine‐induced SLE.