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Purification and characterisation of a novel papain inhibitor from common bean ( Phaseolus vulgaris ) seed
Author(s) -
Santino Angelo,
Gallo Antonia,
Leone Antonella,
Poltronieri Palmiro,
Zacheo Giuseppe
Publication year - 1998
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1034/j.1399-3054.1998.1040301.x
Subject(s) - papain , phaseolus , cystatin , biochemistry , protease , biology , molecular mass , cysteine , protease inhibitor (pharmacology) , proteases , cysteine protease , chemistry , enzyme , botany , cystatin c , human immunodeficiency virus (hiv) , renal function , antiretroviral therapy , viral load , immunology
A proteinaceous inhibitor of papain was purified to apparent homogeneity from mature seeds of common bean ( Phaseolus vulgaris L.). After four chromatographic steps, the papain inhibitor was purified 219‐fold with 12% recovery. On the basis of papain inhibitory activity, cystatins have been estimated to account for about 0.1% of the total protein content of mature common bean seeds. The purified protein, as other plant cystatins, is an acidic protein, heat stable and insensitive to reducing agents. Its molecular mass is about 37 kDa as judged by size exclusion chromatography and SDS‐PAGE. Moreover it is immunologically related to oryzacystatins, since it is recognised by a specific oryzacystatin I antiserum. Based on its biochemical properties the papain inhibitor described here belongs to the phytocystatin family. Papain inhibitory assays carried out during seed development showed that bean cystatin is active since early maturation stages. Our results suggest that, in common bean seed, cysteine proteinase inhibitors are important during seed development with a putative role in the control and regulation of endogenous thiol protease activity.