TY - JOUR
T1 - Identification of Crotonaldehyde as a Hepatic Microsomal Metabolite Formed by α-Hydroxylation of the Carcinogen N-Nitrosopyrrolidine
AU - Wang, Mingyao
AU - Chung, Fung Lung
AU - Hecht, Stephen S.
PY - 1988/1
Y1 - 1988/1
N2 - Crotonaldehyde (2-butenal), which reacts with DNA and is mutagenic and carcinogenic, was identified as a hepatic microsomal metabolite of the hepatocarcinogen N-nitrosopyrrolidine. Incubation mixtures of N-nitrosopyrrolidine, cofactors, and hepatic microsomes from Aroclor pretreated or control F344 rats were derivatized with (2, 4-dinitrophenyl)hydrazine reagent and the resulting mixtures analyzed by high-performance liquid chromatography. Crotonaldehyde (2, 4-dinitrophenyl)hydrazone was identified by its retention time in two different systems and by its ultraviolet and mass spectrum. The ratio of 4-hydroxybutyraldehyde, which has previously been identified as a metabolite of NPYR, to crotonaldehyde was 1.5-2 over a range of substrate concentrations. The approximate values of Km and vmax for crotonaldehyde were 5.8 mM and 0.6 nmol/min/mg of protein and for 4-hydroxybutyraldehyde 14.1 mM and 1.7 nmol/min/mg of protein, for substrate concentrations between 1 and 8 mM, with microsomes from Aroclor pretreated rats. The ratio of 4-hydroxybutyraldehyde to crotonaldehyde was 1.9 upon esterase-catalyzed solvolysis of α-acetoxy-N-nitrosopyrrolidine, a stable precursor to the initial product of N-nitrosopyrrolidine α-hydroxylation. These results demonstrate that crotonaldehyde is formed upon metabolic α-hydroxylation of N-nitrosopyrrolidine and suggest that it may be involved in N-nitrosopyrrolidine-macromolecule interactions.
AB - Crotonaldehyde (2-butenal), which reacts with DNA and is mutagenic and carcinogenic, was identified as a hepatic microsomal metabolite of the hepatocarcinogen N-nitrosopyrrolidine. Incubation mixtures of N-nitrosopyrrolidine, cofactors, and hepatic microsomes from Aroclor pretreated or control F344 rats were derivatized with (2, 4-dinitrophenyl)hydrazine reagent and the resulting mixtures analyzed by high-performance liquid chromatography. Crotonaldehyde (2, 4-dinitrophenyl)hydrazone was identified by its retention time in two different systems and by its ultraviolet and mass spectrum. The ratio of 4-hydroxybutyraldehyde, which has previously been identified as a metabolite of NPYR, to crotonaldehyde was 1.5-2 over a range of substrate concentrations. The approximate values of Km and vmax for crotonaldehyde were 5.8 mM and 0.6 nmol/min/mg of protein and for 4-hydroxybutyraldehyde 14.1 mM and 1.7 nmol/min/mg of protein, for substrate concentrations between 1 and 8 mM, with microsomes from Aroclor pretreated rats. The ratio of 4-hydroxybutyraldehyde to crotonaldehyde was 1.9 upon esterase-catalyzed solvolysis of α-acetoxy-N-nitrosopyrrolidine, a stable precursor to the initial product of N-nitrosopyrrolidine α-hydroxylation. These results demonstrate that crotonaldehyde is formed upon metabolic α-hydroxylation of N-nitrosopyrrolidine and suggest that it may be involved in N-nitrosopyrrolidine-macromolecule interactions.
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U2 - 10.1021/tx00001a005
DO - 10.1021/tx00001a005
M3 - Article
C2 - 2979707
AN - SCOPUS:0023925366
SN - 0893-228X
VL - 1
SP - 28
EP - 31
JO - Chemical research in toxicology
JF - Chemical research in toxicology
IS - 1
ER -