LYSINE ADDUCTS BETWEEN METHYLTETRAHYDROPHTHALIC ANHYDRIDE AND COLLAGEN IN GUINEA-PIG LUNG

The formation of adducts between methyltetrahydrophthalic anhydride (M THPA), an important industrial chemical and potent allergen, and colla gen from guinea pig lung tissue was investigated, Collagen peptides we re obtained from the lung tissue by homogenization, defatting, washing , and digestion with collagenase, In experiments in vitro, lung tissue was exposed to 8.4 mu mol (50 mu Ci) of C-14 MTHPA, The amount of add ucts was 97 nmol MTHPA/g of wet tissue as determined from the bound ra dioactivity, In a study in vivo, four guinea pigs were injected intrat racheally with 8.4 mu mol of C-14 MTHPA each. The amount of adducts wa s 0-1,2 nmol MTHPA/g of wet tissue (determined by bound radioactivity) . N epsilon-methyltetrahydrophthaloyl-L-lysine (MTHPL) was synthesized and characterized by NMR, UV, and mass spectrometry (MS). A method to analyze MTHPL, after derivatization with methanol and pentafluorobenz oyl chloride, using gas chromatography-MS was developed. Analysis of P ronase-digested MTHPA-exposed lung tissue showed a concentration of 19 nmol MTHPL/g wet lung in vitro and between 0 and 0.15 nmol MTHPL/g we t lung in vivo. Thus, 20% in vitro and 12-15% in vivo of the bound rad ioactivity was found as adducts with lysine. These results are a first step toward studies of allergenic epitopes in proteins and methods fo r biological monitoring of exposure to acid anhydrides. (C) 1995 Acade mic Press,Inc.