A plant chloroplast glutamyl proteinase

A glutamyl proteinase was partially purified from Percoll gradient-purified spinach (Spinacia oleracea) chloroplast preparations and appeared to be predominantly localized in the chloroplast stroma. The enzyme degraded casein, but of the 11 synthetic endopeptidase substrates tested, only benzyloxyca...

Full description

Saved in:
Bibliographic Details
Published in:Plant physiology (Bethesda) 1997-06, Vol.114 (2), p.715-722
Main Authors: Laing, W.A. (HortResearch, Auckland, New Zealand.), Christeller, J.T
Format: Article
Language:English
Subjects:
ACTIVIDAD ENZIMATICA
ACTIVITE ENZYMATIQUE
Agronomy. Soil science and plant productions
Biochemistry and Enzymology
Biological and medical sciences
CASEIN
CASEINA
CASEINE
CHEMICAL COMPOSITION
CHEMICOPHYSICAL PROPERTIES
CHLOROPLASTE
CHLOROPLASTS
Chromatography
CLOROPLASTO
COMPOSICION QUIMICA
COMPOSITION CHIMIQUE
CULTURE MEDIA
Economic plant physiology
Electrophoresis
Enzymes
ENZYMIC ACTIVITY
Fundamental and applied biological sciences. Psychology
Gels
GLUTAMINA
GLUTAMINE
Insulin
LOCALIZATION
MEDIO DE CULTIVO
Metabolism
MILIEU DE CULTURE
Nutrition. Photosynthesis. Respiration. Metabolism
Plant cells
Plant physiology and development
Plants
PROPIEDADES FISICOQUIMICAS
PROPRIETE PHYSICOCHIMIQUE
PROTEASAS
PROTEASE
Protease inhibitors
PROTEASES
PROTEINAS
PROTEINE
PROTEINS
PURIFICACION
PURIFICATION
Spinach
SPINACIA OLERACEA
SUBSTRATES
Citations: Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:A glutamyl proteinase was partially purified from Percoll gradient-purified spinach (Spinacia oleracea) chloroplast preparations and appeared to be predominantly localized in the chloroplast stroma. The enzyme degraded casein, but of the 11 synthetic endopeptidase substrates tested, only benzyloxycarbonyl-leucine-leucine-glutamic acid-beta-napthylamide was hydrolyzed at measurable rates. In addition, the enzyme cleaved the oxidized beta-chain of insulin after a glutamic acid residue. There was no evidence that native ribulose-1,5-bisphosphate carboxylase/oxygenase was cleaved by this proteinase. The apparent Km for benzyloxycarbonyl-leucine-leucine-glutamic acid-beta NA at the pH optimum of 8.0 was about 1 mM. Cl- ions were required for both activity and stability. Of the proteinase inhibitors covering all four classes of the endopeptidases, only 4-(2-aminoethyl)-benzenesulfonyl-fluoride HCl and L-1-chloro-3-[4-tosylamido]-4-phenyl-2-butanone significantly inhibited the proteinase. The partially purified enzyme had a molecular weight of about 350,000 to 380,000, based on size-exclusion chromatography. The enzyme has both similar and distinctive properties to those of the bacterial glutamyl proteinases. To our knowledge, this is the first description of a plant glutamyl proteinase found predominantly or exclusively in the chloroplast
ISSN:0032-0889
1532-2548
DOI:10.1104/pp.114.2.715