Barlowe C K, Appling D R
Clayton Foundation Biochemical Institute, Department of Chemistry, University of Texas 78712.
Biochem Biophys Res Commun. 1988 Nov 30;157(1):245-9. doi: 10.1016/s0006-291x(88)80039-1.
C1-tetrahydrofolate synthase (C1-THF synthase) is a trifunctional enzyme which catalyzes the interconversion of one-carbon units attached to the coenzyme THF. Nitrous oxide (N2O) inhalation is known to inactivate hepatic cobalamin-dependent methionine synthase leading to methionine deficiency and trapping of THF in the methyl-THF form. Liver tissue from rats exposed to N2O for 48 hours exhibited a coordinate decrease in all three activities of C1-THF synthase of approximately 25%. A corresponding 25% decrease in immunoreactive C1-THF synthase was also observed after 48 hours. Thus, the decrease in the concentration of C1-THF synthase accounted entirely for the decreases observed in the three activities. These results suggest that perturbations of hepatic THF pools by N2O affect the level of C1-THF synthase expression at a translational or pretranslational level.
C1-四氢叶酸合酶（C1-THF合酶）是一种三功能酶，可催化与辅酶四氢叶酸（THF）相连的一碳单位的相互转化。已知吸入一氧化二氮（N2O）会使肝脏中依赖钴胺素的蛋氨酸合酶失活，导致蛋氨酸缺乏，并使THF以甲基-THF形式滞留。暴露于N2O 48小时的大鼠肝脏组织中，C1-THF合酶的所有三种活性均协同下降约25%。48小时后还观察到免疫反应性C1-THF合酶相应下降25%。因此，C1-THF合酶浓度的降低完全解释了观察到的三种活性的下降。这些结果表明，N2O对肝脏THF库的扰动在翻译或翻译前水平影响C1-THF合酶的表达水平。
