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 (70) Citing Articles via Google Scholar Google Scholar Articles by Hammerton, R. W. Articles by Ho, T.-H. D. Search for Related Content PubMed PubMed Citation Articles by Hammerton, R. W. Articles by Ho, T.-H. D. Agricola Articles by Hammerton, R. W. Articles by Ho, T.-H. D.

Articles

Hormonal Regulation of the Development of Protease and Carboxypeptidase Activities in Barley Aleurone Layers ¹

Department of Plant Biology, University of Illinois, Urbana, Illinois 61801-4777, Department of Biology, Washington University, St. Louis, MO 63130

Carboxypeptidase and protease activities of hormone-treated barley (Hordeum vulgare cv Himalaya) aleurone layers were investigated using the substrates N-carbobenzoxy-Ala-Phe and hemoglobin. A differential effect of gibberellic acid (GA₃) on these activities was observed. The carboxypeptidase activity develops in the aleurone layers during imbibition without the addition of hormone, while the release of this enzyme to the incubation medium is enhanced by GA₃. In contrast, GA₃ is required for both the production of protease activity in the aleurone layer and its secretion. The time course for development of protease activity in response to GA₃ is similar to that observed for -amylase. Treating aleurone layers with both GA₃ and abscisic acid prevents all the GA₃ effects described above. Carboxypeptidase activity is maximal between pH 5 and 6, and is inhibited by diisopropylfluorophosphate and p-hydroxymercuribenzoate. We have observed three protease activities against hemoglobin which differ in charge but are all 37 kilodaltons in size on sodium dodecyl sulfate polyacrylamide gels. The activity of the proteases can be inhibited by sulfhydryl protease inhibitors, such as bromate and leupeptin, yet is enhanced by 2-fold with 2-mercaptoethanol. In addition, these enzymes appear to be active against the wheat and barley storage proteins, gliadin and hordein, respectively. On the basis of these characteristics and the time course of GA₃ response, it is concluded that the proteases represent the GA₃-induced, de novo synthesized proteases that are mainly responsible for the degradation of endosperm storage proteins.

¹ Supported by United States Department of Agriculture competitive grant AG 82-CRCR-1-1012 and by National Science Foundation grant PCM 80-21632.

This article has been cited by other articles:

				A. Drzymala and W. Bielawski Isolation and characterization of carboxypeptidase III from germinating triticale grains Acta Biochim Biophys Sin, January 1, 2009; 41(1): 69 - 78. [Abstract] [Full Text] [PDF]

				A. M. Shirley and C. Chapple Biochemical Characterization of Sinapoylglucose:Choline Sinapoyltransferase, a Serine Carboxypeptidase-like Protein That Functions as an Acyltransferase in Plant Secondary Metabolism J. Biol. Chem., May 23, 2003; 278(22): 19870 - 19877. [Abstract] [Full Text] [PDF]