This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by Ardila, F. J. Articles by Tandecarz, J. S. Search for Related Content PubMed PubMed Citation Articles by Ardila, F. J. Articles by Tandecarz, J. S. Agricola Articles by Ardila, F. J. Articles by Tandecarz, J. S.

Metabolism and Enzymology

Potato Tuber UDP-Glucose:Protein Transglucosylase Catalyzes Its Own Glucosylation ¹

Instituto de Investigaciones Bioquimicas "Fundación Campomar," Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Patricias Argentinas 435, (1405) Buenos Aires, Argentina, Instituto de Investigaciones Bioquímicas Buenos Aires-Consejo Nacional de Investigaciones Científicas y Técnicas, Patricias Argentinas 435, (1405) Buenos Aires, Argentina

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 -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 -glucan in potato tuber.

This article has been cited by other articles:

				H. Satoh, K. Shibahara, T. Tokunaga, A. Nishi, M. Tasaki, S.-K. Hwang, T. W. Okita, N. Kaneko, N. Fujita, M. Yoshida, et al. Mutation of the Plastidial {alpha}-Glucan Phosphorylase Gene in Rice Affects the Synthesis and Structure of Starch in the Endosperm PLANT CELL, July 1, 2008; 20(7): 1833 - 1849. [Abstract] [Full Text] [PDF]