ISSN:
1432-072X
Keywords:
Anacystis nidulans
;
Cyanobacterium
;
Glutathione
;
Glyceraldehyde-3-phosphate dehydrogenase
;
Redox modulation
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract Glyceraldehyde-3-phosphate dehydrogenase (EC 1.2.1.13; GAPDH) from the cyanobacteriumAnacystis nidulans was activated up to five-fold by reduced glutathione (GSH) in the physiological concentration range (0.1–2 mM GSH). Non-physiological reductants, like dithiothreitol (DTT) and β-mercaptoethanol, also activated the enzyme. Oxidized glutathione (GSSG) had no effect on the cyanobacterial GAPDH but treatment with H2O2 led to a rapid, reversible deactivation of both untreated and GSH-treated enzyme preparations. GSH reversed the inhibition induced by H2O2. An oligomeric form of the enzyme (apparentM r∼440,000) was dissociated by GSH into a lower-M r, more active enzyme form (M r∼200,000). The enzyme was shown to obey regular Michaelis-Menten kinetics. The activation of GAPDH by GSH was associated with a decrease inK m and an increase inV max values of the enzyme for 3-phosphoglycerate. GSH had virtually no effect on a GAPDH preparation isolated from corn chloroplasts and studied for comparison.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00943760
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