Abrams B B, Hackel R, Mizunaga T, Lampen J O
J Bacteriol. 1978 Sep;135(3):809-17. doi: 10.1128/jb.135.3.809-817.1978.
A mutant strain of Saccharomyces cerevisiae (D10-ER1) has been isolated after a two-step mutagenesis of strain 4059-358D (SUC 1) using ethyl methane sulfonate. Cells of this new strain produced a level of total invertase equaling that of 4059 but contained only trace amounts of the small, internal, aglycan form of the enzyme (less than 0.1% of total in D10-ER1 compared with 6% in 4059). When D10.ER1 was crossed with an invertase-hyperproducing strain dgr3 (SUC3), progeny were isolated (HZ400-5A and HZ400-2C) in which levels of total invertase had at least quadrupled. The percentage of small invertase, however, remained insignificant. Levels of small invertase in strain HZ400-5A were determined by affinity chromatography on conconavalin A-Sepharose, gel permeation chromatography, and isopycnic centrifugation in CsCl. The large invertase of the SUC1 yeasts described here was found to contain a form apparently greater in size than the large invertase of the SUC2 strain FH4C; this probably reflects a higher content of carbohydrate. The overall results of this study do not support a direct structural relationship between large and small invertases. The implications on invertase biosynthesis and structure are discussed.
使用甲磺酸乙酯对4059 - 358D（SUC 1）菌株进行两步诱变后，分离得到了酿酒酵母的一个突变菌株（D10 - ER1）。该新菌株细胞产生的总转化酶水平与4059菌株相当，但仅含有痕量的酶的小的、内部的、无糖基形式（D10 - ER1中占总量不到0.1%，而4059中为6%）。当D10.ER1与转化酶高产菌株dgr3（SUC3）杂交时，分离得到了子代（HZ400 - 5A和HZ400 - 2C），其中总转化酶水平至少增加了四倍。然而，小转化酶的百分比仍然微不足道。通过刀豆球蛋白A - 琼脂糖亲和层析、凝胶渗透层析和在CsCl中的等密度离心法测定了菌株HZ400 - 5A中小转化酶的水平。发现这里描述的SUC1酵母的大转化酶含有一种大小明显大于SUC2菌株FH4C的大转化酶的形式；这可能反映了更高的碳水化合物含量。本研究的总体结果不支持大、小转化酶之间存在直接的结构关系。文中讨论了对转化酶生物合成和结构的影响。
