11S storage globulin from pumpkin seeds: Regularities of proteolysis by papain
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Limited proteolysis of the α- and β-chains and deep cleavage of the αβ-subunits by the cooperative (one-by-one) mechanism was observed in the course of papain hydrolysis of cucurbitin, an 11S storage globulin from seeds of the pumpkin Cucurbita maxima. An independent analysis of the kinetics of the limited and cooperative proteolyses revealed that the reaction occurs in two successive steps. In the first step, limited proteolysis consisting of detachments of short terminal pep-tides from the α- and β-chains was observed. The cooperative proteolysis, which occurs as a pseudo-first order reaction, started at the second step. Therefore, the limited proteolysis at the first step plays a regulatory role, impacting the rate of deep degradation of cucurbitin molecules by the cooperative mechanism. Structural alterations of cucurbitin induced by limited proteolysis are suggested to generate its susceptibility to cooperative proteolysis. These alterations are tentatively discussed on the basis of the tertiary structure of the cucurbitin subunit pdb|2EVX in comparison with previously obtained data on features of degradation of soybean 11S globulin hydrolyzed by papain.
Key wordsCucurbita maxima seed storage globulin limited proteolysis papain kinetics
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- 3.Shutov, A. D., and Wilson, K. A. (2014) Seed storage globulins: their descent from bacterial ancestors and mechanisms of degradation, in Globulins: Biochemistry, Production and Role in Immunity (Milford, S. D., ed.) Nova Science Publishers, New York, pp. 71–104.Google Scholar
- 8.Shutov, A. D., Rudakova, A. S., Rudakov, S. V., Kakhovskaya, I. A., Schallau, A. A., Wilson, K. A., and Maruyama, N. (2013) Degradation of β-conglycinin β-homotrimer by papain: independent occurrence of limited and extensive proteolyses, Biosci. Biotechnol. Biochem., 77, 2082–2086.PubMedCrossRefGoogle Scholar
- 9.Zakharov, A., Carchilan, M., Stepurina, T., Rotari, V., Wilson, K., and Vaintraub, I. (2004) Comparative study of the role of the major proteinases of germinated common bean (Phaseolus vulgaris L.) and soybean (Glycine max (L.) Merrill) seeds in the degradation of their storage proteins, J. Exp. Bot., 55, 2241–2249.PubMedCrossRefGoogle Scholar