The genetics and biochemistry of urease in Ustilago violacea
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- Baird, M.L. & Garber, E.D. Biochem Genet (1981) 19: 1101. doi:10.1007/BF00484568
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Two complementing loci in different linkage groups of the basidiomycete Ustilago violacea are involved in urease activity: a structural one (ure-1) and a second inferred to involve a permease (ure-2) locus. Two types of complementing mutations occur in the structural locus: null activity (ure-1a) and obviously reduced activity (ure-1b). The ure-2 mutants lacked urease activity in vivo on the phenol red-urea test medium, but gave extracts with wild-type activity. Extracts from wild-type strains gave one site of urease activity after polyacrylamide gel electrophoresis. A number of ure-1b mutants and active revertants from ure-1a mutants yielded electrophoretically variant urease sites. The results are discussed in terms of enzyme polymorphism in haploid eukaryotes by one (missense) or two (null, then missense) mutations.