Schaaff I, Heinisch J, Zimmermann F K
Institut für Mikrobiologie, Darmstadt, F.R.G.
Yeast. 1989 Jul-Aug;5(4):285-90. doi: 10.1002/yea.320050408.
Eight different enzymes for glycolysis and alcoholic fermentation were overproduced in a common Saccharomyces cerevisiae strain by placing their genes on multicopy vectors. The specific enzyme activities were increased between 3.7- and 13.9-fold above the wild-type level. The overproduction of the different glycolytic enzymes had no effect on the rate of ethanol formation, even with those enzymes that catalyse irreversible steps: hexokinase, phosphofructokinase and pyruvate kinase. Also the simultaneous increase in the activities of pairs of enzymes such as pyruvate kinase and phosphofructokinase or pyruvate decarboxylase and alcohol dehydrogenase, did not increase the rate of ethanol production. The levels of key glycolytic metabolites were also normal, compared to the reference strain.
通过将参与糖酵解和酒精发酵的8种不同酶的基因置于多拷贝载体上，在一种常见的酿酒酵母菌株中过量表达这些酶。其比酶活比野生型水平提高了3.7至13.9倍。不同糖酵解酶的过量表达对乙醇形成速率没有影响，即使是那些催化不可逆步骤的酶：己糖激酶、磷酸果糖激酶和丙酮酸激酶。丙酮酸激酶和磷酸果糖激酶或丙酮酸脱羧酶和乙醇脱氢酶等酶对的活性同时增加，也不会提高乙醇的产生速率。与参考菌株相比，关键糖酵解代谢物的水平也正常。
