Nine sucrose nonfermenting mutants have been isolated from yeast strain EK-6B, carrying the tightly linked SUC3 and MAL3 genes. These mutants are allelic to the SUC3 gene recessive in nature and none of them has detectable levels of either internal or external invertase. A single point mutation lead
Genetic control of invertase formation in Saccharomyces cerevisiae
โ Scribed by Hackel, R. A. ;Khan, N. A.
- Publisher
- Springer
- Year
- 1978
- Tongue
- English
- Weight
- 688 KB
- Volume
- 164
- Category
- Article
- ISSN
- 0026-8925
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โฆ Synopsis
Invertase formation in the yeast Saccharomyces cerevisiae is subject to repression by hexoses in the growth medium. Mutagen-induced (ethyl methanesulfonate or N-methyl-N-nitro-nitrosoguanidine) invertase hyperproducer mutants have been derived from the SUC3 MAL3 strain EK-6B by selecting for their ability to grow on media containing the sugar raffinose plus 2-deoxy-D-glucose (2DG). Raffinose like sucrose is a betta-fructoside which can be hydrolyzed by yeast invertase (beta-fructoside which can be hydrolyzed by yeast invertase (beta-fructofuranoside fructohydrolase). These mutants, designated dgr, produce higher levels of invertase (pi-glucosidase levels are also elevated but to a lesser extent) under conditions normally repressing invertase biosynthesis in the parent. Invertases of mutants dgr2 and dgr3 are indistinguishable from that of EK-6B with respect to their Km's for sucrose and thermal labilities. Genetic studies revealed that dgr2 and dgr3 are recessive and unlinked to the SUC3 gene.
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