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 Tools annual

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 monthly

Global: Zendy Plus monthly

Presents the access of premium content as premium feature

Premium Content

Global: Zendy Plus annual

Global: Zendy Free Plan

Phosphoenolpyruvate carboxykinase (PEPCK) was purified to homogeneity from the moderately halophilic bacterium Vibrio costicola. The enzyme is monomeric, with an Mr of 62,000, as determined by the Svedberg equation, by using values of s0(20,w) 4.4 x 10(-13) s, D20,w 6.13 x 10(-7) cm2.s-1 and v 0.719 cm3.g-1. Compared with other, non-halophilic, PEPCKs, the enzyme from V. costicola had a significantly lower total content of hydrophobic amino acids. The contents of glycine and serine were higher in the V. costicola enzyme (16.7 and 10.22% respectively) than in the non-halophilic PEPCKs (6.8-9.6% and 4.67-6.28% respectively). These results resemble those obtained by De Médicis &amp; Rossignol [(1979) Experientia 35, 1546-1547] with the pyruvate kinase from V. costicola, and agree with the proposal by Lanyi [(1974) Bacteriol. Rev. 38, 272-290] of partial replacement of hydrophobic amino acids by glycine and serine to maintain the balance between hydrophobic and hydrophilic forces in halophilic enzymes. In agreement with this 'halophilic' characteristic, the PEPCK was somewhat stabilized by 1 M-KCl or -NaCl and by 20% (v/v) glycerol, and its oxaloacetate-decarboxylation and 14CO2-oxaloacetate-exchange reactions were activated by KCl and NaCl up to 1 M, whereas the fixation of CO2 on PEP had a maximum at 0.025-0.05 M salt. These facts suggest that the salts, at concentrations probably physiological for the bacterium, increase the formation of the complex of oxaloacetate and ATP with the enzyme, and the liberation of the products, PEP and ADP, thus favouring PEP synthesis.

biochemical journal

Phosphoenolpyruvate carboxykinase from the moderate halophile <i>Vibrio costicola</i>. Purification, physicochemical properties and the effect of univalent-cation salts

Phosphoenolpyruvate carboxykinase from the moderate halophile Vibrio costicola. Purification, physicochemical properties and the effect of univalent-cation salts