Potato tuber UDP-Glucose: Protein transglucosylase catalyzes its own glucosylation
Potato (Solanum tuberosum L.) tuber UDP-glucose:protein transglucosylase (UPTG) (EC 2.4.1.112) is involved in the first of a two-step mechanism proposed for protein-bound α-glucan synthesis by catalyzing the covalent attachment of a single glucose residue to an acceptor protein. The resulting glucos...
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| Autores principales: | , |
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| Formato: | Artículo publishedVersion |
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1992
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| Acceso en línea: | http://hdl.handle.net/20.500.12110/paper_00320889_v99_n4_p1342_Ardila https://repositoriouba.sisbi.uba.ar/gsdl/cgi-bin/library.cgi?a=d&c=artiaex&d=paper_00320889_v99_n4_p1342_Ardila_oai |
| Aporte de: |
| Sumario: | Potato (Solanum tuberosum L.) tuber UDP-glucose:protein transglucosylase (UPTG) (EC 2.4.1.112) is involved in the first of a two-step mechanism proposed for protein-bound α-glucan synthesis by catalyzing the covalent attachment of a single glucose residue to an acceptor protein. The resulting glucosylated 38-kilodalton polypeptide would then serve as a primer for enzymic glucan chain elongation during the second step. In the present report, we describe the fast protein liquid chromatography purification of UPTG from a membrane pellet of potato tuber. An apparently close association of UPTG, phosphorylase, and starch synthase was observed under native conditions during different purification steps. Enrichment of a 38-kilodalton polypeptide was found throughout enzyme purification. It is now shown that the purified UPTG, with an apparent molecular mass of 38 kilodaltons, undergoes self-glucosylation in a UDP-glucose- and Mn2+-dependent reaction. Therefore, it is concluded that UPTG is the enzyme and at the same time the priming protein required for the biogenesis of protein-bound α-glucan in potato tuber. |
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