The regulation of heme biosynthesis.
The regulation of heme biosynthesis.
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发表时间：
1976
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通讯作者：
R. Poulson
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作者：
R. Poulson
研究了酿酒酵母在葡萄糖去阻抑和呼吸适应过程中细胞和原生质体中血红素生物合成酶水平的变化。在好氧或厌氧葡萄糖降压或3‘，5’环AMP存在下，β-氨基酮丙酸脱水酶、原卟啉原氧化酶和铁络合酶水平升高，而催化胆红素原向原卟啉原IX反应的酶水平保持不变。相反，β-氨基乙酰丙酸合成酶在有氧葡萄糖去阻抑和3‘，5’环AMP存在时降低，但在无氧去阻抑过程中保持不变。在有氧葡萄糖去抑制过程中，细胞的血红素含量增加，而在无氧去抑制过程中，细胞的血红素含量没有增加。结果表明，在酵母中，厌氧菌对血红素合成的抑制作用至少部分是由于原卟啉原IX氧化对氧的需求，葡萄糖对血红素生物合成的影响是通过葡萄糖对原卟啉原氧化酶和可能的铁络合酶的抑制而实现的。
Changes in the levels of the heme biosynthetic enzymes were studied in cells and protoplasts of Saccharomyces cerevisiae during glucose derepression and respiratory adaptation. On aerobic or anaerobic glucose derepression or in the presence of 3', 5' cyclic AMP the levels of beta-aminolevulinic acid dehydratase, protoporphyrinogen oxidase and ferrochelatase increased whereas the levels of the enzymes catalysing the reactions from porphobilinogen to protoporphyrinogen IX remained constant. In contrast, the level of beta-aminolevulinic acid synthetase decreased during aerobic glucose derepression and in the presence of 3', 5' cyclic AMP, but it remained unchanged during anaerobic derepression. The heme content of the cells increased during aerobic glucose derepression but no increase was observed during anaerobic derepression of the cells. It is concluded that, in yeast, the inhibitory effect of anaerobiosis on heme synthesis is due, at least in part, to the requirement for oxygen in the oxidation of protoporphyrinogen IX, and that the effect of glucose on heme biosynthesis is mediated via glucose repression of protoporphyrinogen oxidase and possibly ferrochelatase.