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 Bond, H. M. Articles by Bowles, D. J. Search for Related Content PubMed PubMed Citation Articles by Bond, H. M. Articles by Bowles, D. J. Agricola Articles by Bond, H. M. Articles by Bowles, D. J.

Articles

Characterization of Soybean Endopeptidase Activity Using Exogenous and Endogenous Substrates ¹

Department of Biochemistry, University of Leeds, Leeds, LS2 9JT United Kingdom

Endopeptidase activity in mature soybean seeds (Glycine max), has been measured using an exogenous substrate, [¹²⁵I]iodoinsulin B chain. On the basis of pH optimum and the use of specific proteinase inhibitors, two distinct endopeptidase activities can be identified in both the embryonic axis and the cotyledons. One activity is characteristic of a neutral/alkaline metalloendopeptidase(s) and the other of an acidic carboxylendopeptidase(s). Neither activity is membrane-bound. The metalloendopeptidase(s), most probably working with neutral expopeptidases also present in the tissues, is capable of degrading certain subunits of the storage proteins. The subunit of conglycinin and additional seed polypeptides remain resistant to degradation. The carboxylpeptidase activity displayed a different specificity towards endogenous substrates; in particular, an acid-soluble polypeptide of apparent molecular weight 30,000 appeared to be the principal substrate for limited proteolytic degradation by the proteinase(s). Soybean agglutinin remained resistant to degradation by either class of endopeptidases.

This article has been cited by other articles:

				K. Muntz, M.A. Belozersky, Y.E. Dunaevsky, A. Schlereth, and J. Tiedemann Stored proteinases and the initiation of storage protein mobilization in seeds during germination and seedling growth J. Exp. Bot., September 1, 2001; 52(362): 1741 - 1752. [Abstract] [Full Text] [PDF]