Purification of UDP-galactose: diacylglycerol galactosyltransferase from chloroplast envelopes of spinach (Spinacia oleracea L.) |
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Authors: | T Teucher E Heinz |
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Institution: | (1) Institut für Allgemeine Botanik, Universität Hamburg, Ohnhorststrasse 18, W-2000 Hamburg 52, Germany |
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Abstract: | Uridine 5-diphosphate(UDP)-galactose: 1,2-diacylglycerol 3-O--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 -–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 M for UDP-galactose with dioleoylglycerol as acceptor and could not be activated by addition of other lipids.Abbreviations CHAPS
3-(3-cholamidopropyl)dimethylammonio]-propanesulfonate
- DTE
dithioerythritol
- MGD
monogalactosyl diacylglycerol
- PMSF
phenylmethanesulfonyl fluoride
- SDS-PAGE
sodium dodecyl sulfate-polyacrylamide gel electrophoresis
This work was supported by the Deutsche Forschungsgemeinschaft. |
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Keywords: | Chloroplast envelope Galactosyltransferase (EC 2 4 1 46) Membrane protein (purification) Polypeptide 22 kilodalton (chloroplast envelope) Spinacia |
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