English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Nine new hem12 haploid mutants of baker's yeast (Saccharomyces cerevisiae), totally or partially deficient in uroporphyrinogen decarboxylase activity, were subjected to both genetic and biochemical analysis. The mutations sites studied are situated far apart within the HEM12 gene located on chromosome IV. Uroporphyrinogen decarboxylase activity in the cell-free extracts of the mutants was decreased by 50-100%. This correlated well with the decrease of haem formation and the increased accumulation and excretion of porphyrins observed in vivo. The pattern of porphyrins (uroporphyrin and its decarboxylation products) accumulated in the cells of mutants partially deficient in uroporphyrinogen decarboxylase activity did not differ significantly, although differences in vitro were found in the relative activity of the mutant enzyme at the four decarboxylation steps. The excreted porphyrins comprised mainly dehydroisocoproporphyrin or pentacarboxyporphyrin. In heterozygous hem12-1/HEM12 diploid cells, a 50% decrease in decarboxylase activity led to an increased accumulation of porphyrins as compared with the wild-type HEM12/HEM12 diploid, which points to the semi-dominant character of the hem12-1 mutation. The biochemical phenotypes of both the haploid and the heterozygous diploid resembles closely the situation encountered in porphyria cutanea tarda, the most common human form of porphyria.

biochemical journal

The effects in vivo of mutationally modified uroporphyrinogen decarboxylase in different hem12 mutants of baker's yeast (Saccharomyces cerevisiae)