ISSN:
1399-3054
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Biology
Notes:
The synthesis of homoglutathione (hGSH) by several plants of the tribe Phaseoleae is shown to be catalysed by a β-alanine-specific hGSH synthetase, Properties of the enzyme from Phaseolus coccineus L. cv. Preisgewinner were studied, using ammonium sulfate precipitates of primary leaf extracts. The hGSH synthetase showed a broad pH optimum at pH 8–9, an absolute requirement for Mg2+, a stimulation by K+, and a high affinity for γ-glutamylcysteine [Km(app.) 73 μM]. The enzyme exhibited a high specificity for β-alanine [Km(app.) 1.34 mM] compared to glycine [Km(app.) 98 mM]. Chloroplasts, isolated from the leaves of Phaseolus coccineus, contained about 17% of the hGSH synthetase activity in the leaf cells.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1399-3054.1988.tb02045.x
Permalink
