Expression of an endopeptidase (EP-C1) in Phaseolus vulgaris plants

• Published in: Plant physiology (Bethesda) Vol. 101; no. 2; pp. 421 - 427
• Main Authors: Tanaka, T, Minamikawa, T, Yamauchi, D, Ogushi, Y
• Format: Journal Article
• Language: English
• Published: Rockville, MD American Society of Plant Physiologists 01.02.1993
• Subjects: ACTIVIDAD ENZIMATICA; ACTIVITE ENZYMATIQUE; Antiserum; Biological and medical sciences; COMPOSICION QUIMICA; COMPOSITION CHIMIQUE; Cotyledons; Enzymes; Fructification and ripening; FRUITS; FRUTAS; Fundamental and applied biological sciences. Psychology; Gels; GRAINE; Immunoblotting; Messenger RNA; Molecular Biology and Gene Regulation; PEPTIDASAS; PEPTIDASE; PESO MOLECULAR; PHASEOLUS VULGARIS; Plant physiology and development; POIDS MOLECULAIRE; PROTEINAS; PROTEINE; PURIFICACION; PURIFICATION; Seed pods; Seedlings; Seeds; SEMILLA; Vegetative and sexual reproduction, floral biology, fructification; VIGNA MUNGO; Seeds; Purification; Pod; Enzyme; Immunological method; Characterization; Leguminosae; Vegetable crop; Enzymatic activity; Phaseolus vulgaris; Dicotyledones; Endopeptidase; Angiospermae; Spermatophyta; Developmental stage
• ISSN: 0032-0889; 1532-2548
• DOI: 10.1104/pp.101.2.421

Endopeptidase activity increases continually in pods of maturing fruits of French bean (Phaseolus vulgaris L cv Goldstar) plants and is thought to participate in the protein mobilization in pods during the development of seeds (M. Endo, T. Minamikawa, D. Yamauchi, W. Mitsuhashi [1987] J Exp Bot 38: 1988-1995). In the present studies, one of the major endopeptidase forms, designated EP-C1, was purified as a 34-kD polypeptide from pods of maturing French bean fruits. EP-C1 was found to be immunologically distinguished from other forms in extracts from pods, but homologous to SH-EP, the major cysteine endopeptidase expressed in cotyledons of germinating Vigna mungo seeds (W. Mitsuhashi, T. Minamikawa [1989] Plant Physiol 89: 274-279). The level of endopeptidase that reacted with the antiserum to EP-C1 increased in pods as the fruit maturation proceeded. EP-C1 was also immunologically detected in stems of French bean plants bearing fruits of later maturation stages. Protein immunoblotting showed that a 34-kD polypeptide corresponding to EP-C1 in molecular mass occurred in extracts from 7- to 9-d cotyledons of germinating French bean seeds. In addition, two other polypeptides with slightly higher molecular masses were observed in extracts from 3- to 5-d cotyledons. We suggest that these two polypeptides are intermediates involved in posttranslational processing of EP-C1. RNA blot hybridization with EP-C1 cDNA as a probe showed that EP-C1 mRNA occurred in pods of fruits at later maturing stages and also in cotyledons of 3- to 7-d germinating seeds