ISOLATION OF GLUCURONIC ACID CONJUGATE OF N-HYDROXY-4-AMINOBIPHENYL FROM DOG URINE AND ITS MUTAGENIC ACTIVITY

Abstract

The glucuronic acid conjugate of N-hydroxy-4-aminobiphenyl (NOH-4-ABP) was isolated in relatively pure form from the urine of dogs given the carcinogen 4-aminobiphenyl, utilizing molecular size, ion exchange, absorption and partition chromatography. This conjugate is an active mutagen in Salmonella typhimurium strains TA1538 and TA98 but not in TA1535 or TA1537. NOH-4-ABP and 4-nitrosobiphenyl are also highly active in TA1538 and TA98 and inactive in TA1535 and TA1537. These observations support the concept that this conjugate is the water-soluble carrier that delivers the active metabolite to the bladder. A substance of identical chromatographic and spectral properties to the conjugate isolated from dog urine was synthesized in low yield by the direct condensation of NOH-4-ABP with glucuronic acid. This substance yields NOH-4-ABP on dilute acid hydrolysis. Sodium (N-4-biphenylhydroxylamino-.beta.-D-glucopyranosid) uronate, the N-O-C isomer, was also synthesized. It had differing chromatographic and chemical properties to the natural conjugate. This evidence suggests that the urinary conjugate is the compound in which conjugation has occurred with the N atom of the hydroxylamine group rather than the O atom.