人类妊娠早期的异源物质氧化：概念组织中过氧化物酶催化的化学氧化

Xenobiotic oxidation during early pregnancy in man: peroxidase catalysed chemical oxidation in conceptual tissues.

Joseph P, Srinivasan S N, Kulkarni A P

Toxicology Program, College of Public Health, MDC, University of South Florida, Tampa 33612.

Xenobiotica. 1994 Jul;24(7):583-90. doi: 10.3109/00498259409043261.

Abstract

A membrane-bound peroxidase activity was isolated and purified from pooled samples of human intrauterine tissue (embryo, placenta, amnion, chorion and uterine decidua) of 4-6 weeks of gestation. 2. The H2O2-dependent guaiacol oxidation catalysed by the purified peroxidase exhibited a specific activity of 10.82 +/- 1.81 mumol/min/mg protein. 3. The optimum conditions required for guaiacol oxidation catalysed by the peroxidase included 18 mM guaiacol, 400 microM H2O2, pH 9.0, and 2 micrograms/ml enzyme protein. The guaiacol oxidation was inhibited by KCN and NaN3 with IC50s of 17.6 and 22 microM, respectively. 4. Several other endogenous and exogenous chemicals also underwent H2O2-dependent oxidation catalysed by the purified peroxidase. These results suggest that peroxidase may be one of the major pathways of xenobiotic oxidation present in organogenesis-stage human conceptual tissues influencing the toxicity of chemicals to which the developing embryo is exposed.

摘要

从妊娠4 - 6周的人子宫内组织（胚胎、胎盘、羊膜、绒毛膜和子宫蜕膜）的混合样本中分离并纯化出一种膜结合过氧化物酶活性物质。2. 纯化后的过氧化物酶催化的依赖过氧化氢的愈创木酚氧化反应的比活性为10.82±1.81微摩尔/分钟/毫克蛋白质。3. 过氧化物酶催化愈创木酚氧化所需的最佳条件包括18毫摩尔愈创木酚、400微摩尔过氧化氢、pH 9.0以及2微克/毫升酶蛋白。愈创木酚氧化反应受到氰化钾和叠氮化钠的抑制，其半数抑制浓度分别为17.6和22微摩尔。4. 其他几种内源性和外源性化学物质也能被纯化后的过氧化物酶催化发生依赖过氧化氢的氧化反应。这些结果表明，过氧化物酶可能是器官发生期人类妊娠组织中存在的外源性物质氧化的主要途径之一，影响发育中胚胎所接触化学物质的毒性。