MECHANISM OF HEME CATABOLISM - STUDY OF HEME BREAKDOWN IN SPLEEN MICROSOMAL FRACTION AND IN A MODEL SYSTEM BY O-18 LABELING AND METAL SUBSTITUTION
MECHANISM OF HEME CATABOLISM - STUDY OF HEME BREAKDOWN IN SPLEEN MICROSOMAL FRACTION AND IN A MODEL SYSTEM BY O-18 LABELING AND METAL SUBSTITUTION
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DOI：
10.1042/bj1740103
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发表时间：
1978-01-01
影响因子：
4.1
通讯作者：
BROWN, SB
中科院分区：
文献类型：
--
作者：
KING, RFGJ;BROWN, SB
用18 O标记大环断裂所需的分子氧，研究了血红素分解形成胆色素的机理。对于通过大鼠脾微粒体血红素加氧酶系统的血红素降解，产物胆红素的质谱分析显示通过2-分子机制发生裂解，即，胆红素中的末端内酰胺O原子衍生自2个不同的O2分子。抗坏血酸和O2耦合氧化降解肌红蛋白是通过2-分子机理进行的。钴和锰配合物的原卟啉IX没有被降解的血红素加氧酶系统或耦合氧化系统。Fe原子具有促进甜菜碱分解的独特性质。
The mechanism of bile-pigment formation from heme breakdown was studied by using 18O labeling of the molecular O2 required for macrocyclic ring cleavage. For heme degradation by the rat spleen microsomal heme oxygenase system, mass spectrometry of the product bilirubin revealed that cleavage occurred by the 2-Molecule Mechanism, i.e., the terminal lactam O atoms in bilirubin were derived from 2 different O2 molecules. Degradation of myoglobin by coupled oxidation with ascorbate and O2 proceeded via the 2-Molecule Mechanism. Co and Mn complexes of protoporphyrin IX were not degraded by either the heme oxygenase system or the coupled oxidation system. The Fe atom possesses unique properties in facilitating prophyrin breakdown.