溶组织内阿米巴的丙酮酸到乙醇途径。
Pyruvate-to-ethanol pathway in Entamoeba histolytica.
作者信息
Lo H S, Reeves R E
出版信息
Biochem J. 1978 Apr 1;171(1):225-30. doi: 10.1042/bj1710225.
The pyruvate-to-ethanol pathway in Entamoeba histolytica is unusual when compared with most investigated organisms. Pyruvate decarboxylase (EC 4.1.1.1), a key enzyme for ethanol production, is not found. Pyruvate is converted into acetyl-CoA and CO2 by the enzyme pyruvate synthase (EC 1.2.7.1), which has been demonstrated previously in this parasitic amoeba. Acetyl-CoA is reduced to acetaldehyde and CoA by the enzyme aldehyde dehydrogenase (acylating) (EC 1.2.1.10) at an enzyme activity of 9 units per g of fresh cells with NADH as a reductant. Acetaldehyde is further reduced by either a previously identified NADP+-linked alcohol dehydrogenase or by a newly found NAD+-linked alcohol dehydrogenase at an enzyme activity of 136 units per g of fresh cells. Ethanol is identified as the product of soluble enzymes of amoeba acting on pyruvate or acetyl-CoA. This result is confirmed by radioactive isotopic, spectrophotometric and gas-chromatographic methods.
与大多数已研究的生物体相比，溶组织内阿米巴中丙酮酸到乙醇的途径不同寻常。未发现乙醇生产的关键酶丙酮酸脱羧酶（EC 4.1.1.1）。丙酮酸通过丙酮酸合酶（EC 1.2.7.1）转化为乙酰辅酶A和二氧化碳，该酶先前已在这种寄生性变形虫中得到证实。乙酰辅酶A在以NADH作为还原剂、每克新鲜细胞9个酶活性单位的情况下，被酰化醛脱氢酶（EC 1.2.1.10）还原为乙醛和辅酶A。乙醛通过先前鉴定的NADP⁺连接的醇脱氢酶或新发现的NAD⁺连接的醇脱氢酶进一步还原，每克新鲜细胞的酶活性为136个单位。乙醇被鉴定为变形虫可溶性酶作用于丙酮酸或乙酰辅酶A的产物。这一结果通过放射性同位素、分光光度法和气相色谱法得到证实
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