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 Web of Science 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 Web of Science (17) Citing Articles via Google Scholar Google Scholar Articles by Kushad, M. M. Articles by Ferro, A. J. Search for Related Content PubMed PubMed Citation Articles by Kushad, M. M. Articles by Ferro, A. J. Agricola Articles by Kushad, M. M. Articles by Ferro, A. J.

Articles

5'-Methylthioadenosine Nucleosidase and 5-Methylthioribose Kinase Activities and Ethylene Production during Tomato Fruit Development and Ripening ¹

Department of Horticulture, Oregon State University, Corvallis, Oregon 97331-3804, Department of Microbiology, Oregon State University, Corvallis, Oregon 97331-3804

5'-Methylthioadenosine (MTA) nucleosidase and 5-methylthioribose (MTR) kinase activities were measured in crude extracts of tomato fruits (Lycopersicon esculentum Mill cv Rutgers) during fruit development and ripening. The highest activity of MTA nucleosidase (1.2 nanomoles per milligram protein per minute) was observed in small green fruits. The activity decreased during ripening; at the overripe stage only 6.5% of the peak activity remained. MTR kinase activity was low at the small green stage and increased thereafter until it reached peak activity at the breaker stage (0.7 nanomoles per milligram protein per minute) followed by a sharp decline at the later stages of fruit ripening. 1-Amino-cyclopropane-1-carboxylic acid (ACC) levels peaked at the red stage, while ethylene reached its highest level at the light-red stage. Several analogs of MTA and MTR were tested as both enzyme and ethylene inhibitors. Of the MTA analogs examined for their ability to inhibit MTA nucleosidase, 5'-chloroformycin reduced enzyme activity 89%, whereas 5'-chloroadenosine, 5'-isobutylthioadenosine, 5'-isopropylthioadenosine, and 5'-ethylthioadenosine inhibited the reaction with MTA by about 40%. 5'-Chloroformycin and 5'-chloroadenosine inhibited ethylene production over a period of 24 hours by about 64 and 42%, respectively. Other analogs of MTA were not effective inhibitors of ethylene production, whereas aminoethoxyvinylglycine showed a 34% inhibition over the same period of time. Of the MTR analogs tested, 5-isobutylthioribose was the most effective inhibitor of both MTR-kinase (41%) and ethylene production (35%).

This article has been cited by other articles:

				G. Rzewuski, K. A. Cornell, L. Rooney, K. Burstenbinder, M. Wirtz, R. Hell, and M. Sauter OsMTN encodes a 5'-methylthioadenosine nucleosidase that is up-regulated during submergence-induced ethylene synthesis in rice (Oryza sativa L.) J. Exp. Bot., April 1, 2007; 58(6): 1505 - 1514. [Abstract] [Full Text] [PDF]

				M. Sauter, K. A. Cornell, S. Beszteri, and G. Rzewuski Functional Analysis of Methylthioribose Kinase Genes in Plants Plant Physiology, December 1, 2004; 136(4): 4061 - 4071. [Abstract] [Full Text] [PDF]