ISSN:
1432-2048
Keywords:
Chloroplast envelope
;
Galactosyltransferase (EC 2.4.1.46)
;
Membrane protein (purification)
;
Polypeptide
;
22 kilodalton (chloroplast envelope)
;
Spinacia
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract Uridine 5′-diphosphate(UDP)-galactose: 1,2-diacylglycerol 3-O-β-d-galactopyranosyltransferase (EC 2.4.1.46) is an integral protein of chloroplast envelope membranes from which it has been partially purified (Covès et al., 1986, FEBS Lett. 208, 401–406). We have worked out a purification procedure which after removal of peripheral membrane proteins, solubilization and two chromotographic steps allowed us to identify a 22-kDa protein as the galactosyltransferase. Enrichment of enzymatic activity was paralleled by an enrichment of this protein and its radioactive derivative obtained by photoaffinity labelling with [α-−32P]UDP which is a potent inhibitor of the enzyme. The purification factor of about 350 is substantially higher than achieved previously and indicates that the enzyme represents less than 0.3% of the envelope proteins. The purified enzyme has a Km of 87 μM for UDP-galactose with dioleoylglycerol as acceptor and could not be activated by addition of other lipids.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00195332
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