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Title: Characterization of. alpha. -amylase-inhibitor, a lectin-like protein in the seeds of Phaseolus vulgaris

The common bean, Phaseolus vulgaris, contains a glycoprotein that inhibits the activity of mammalian and insect {alpha}-amylases but not of plant {alpha}-amylases. It is therefore classified as an antifeedant or seed defense protein. In P. vulgaris cv Greensleeves, {alpha}-amylase inhibitor ({alpha}Al) is present in embryonic axes and cotyledons, but not in other organs of the plant. The protein is synthesized during the same time period that phaseolin and phytohemagglutinin are made and also accumulates in the protein storage vacuoles (protein bodies). All the glycoforms have complex glycans that are resistant to removal by endoglycosidase H, indicating transport of the protein through the Golgi apparatus. The two different polypeptides correspond to the N-terminal and C-terminal halves of a lectin-like protein encoded by an already identified gene or a gene closely related to it. The primary translation product of {alpha}Al is a polypeptide of M{sub r} 28,000. Immunologically cross-reacting glycopolypeptides of M{sub r} 30,000 to 35,000 are present in the endoplasmic reticulum, while the smaller polypeptides (M{sub r} 15,000-19,000) accumulate in protein storage vacuoles (protein bodies). Together these data indicate that {alpha}Al is a typical bean lectin-type protein that is synthesized on the rough endoplasmic reticulum, modified in the Golgi, and transportedmore » to the protein storage vacuoles.« less
Authors:
; ;  [1]
  1. (Univ. of California, San Diego, La Jolla (USA))
Publication Date:
OSTI Identifier:
5859528
Resource Type:
Journal Article
Resource Relation:
Journal Name: Plant Physiology; (USA); Journal Volume: 92:3
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES; AMYLASE; ENZYME INHIBITORS; GLYCOPROTEINS; BIOSYNTHESIS; PHASEOLUS; PHYSIOLOGY; PLANTS; SEEDS; ENZYMES; GLYCOSYL HYDROLASES; HYDROLASES; LEGUMINOSAE; MAGNOLIOPHYTA; MAGNOLIOPSIDA; O-GLYCOSYL HYDROLASES; ORGANIC COMPOUNDS; PROTEINS; SYNTHESIS 550200* -- Biochemistry