Jahn D, Hungerer C, Troup B
Fachbereich Biologie der Universität, Marburg.
Naturwissenschaften. 1996 Sep;83(9):389-400.
The majority of bacteria, all investigated archaea and plants form the general precursor molecule of all tetrapyrroles 5-aminolevulinic acid by a unique transformation of transfer RNA bound glutamate. Only the alpha-group of the proteobacteria, mammals and yeast synthesize 5-aminolevulinic acid via the well known condensation of succinyl-CoA and glycine. The late steps in tetrapyrrole biosynthesis also contain alternative biosynthetic pathways for the formation and oxidative decarboxylation of coproporphyrinogen III. Unusual enzymatic reactions including the utilization of two substrate molecules as cofactor by the porphobilinogen deaminase and the formation of a spiro intermediate are involved in the formation of uroporphyrinogen III. The biosynthesis of hemes in bacteria is strictly regulated at the formation of 5-aminolevulinic acid and the oxidative decarboxylation of coproporphyrinogen III. The involved heme biosynthetic genes are regulated by the environmental concentrations of oxygen, iron, nitrate, growth phase and intracellular levels of heme. The current knowledge on the various enzymatic reactions and gene regulatory mechanisms is reviewed.
大多数细菌、所有已研究的古细菌和植物通过与转运RNA结合的谷氨酸的独特转化形成所有四吡咯的通用前体分子5-氨基乙酰丙酸。只有变形菌纲的α-亚群、哺乳动物和酵母通过琥珀酰辅酶A和甘氨酸的著名缩合反应合成5-氨基乙酰丙酸。四吡咯生物合成的后期步骤还包含原卟啉原III形成和氧化脱羧的替代生物合成途径。尿卟啉原III的形成涉及异常的酶促反应，包括胆色素原脱氨酶将两个底物分子用作辅因子以及形成螺旋中间体。细菌中血红素的生物合成在5-氨基乙酰丙酸的形成和原卟啉原III的氧化脱羧过程中受到严格调控。所涉及的血红素生物合成基因受环境中的氧气、铁、硝酸盐浓度、生长阶段和细胞内血红素水平的调控。本文综述了目前关于各种酶促反应和基因调控机制的知识。
