Phosphorylation of glyoxysomal malate synthase from castor oil seed endosperm and cucumber cotyledon

Journal Article · Sat Apr 01 04:00:00 EST 1989 · Plant Physiology, Supplement; (USA)

OSTI ID:6611070

Yang, Y P; Randall, D D ^[1]

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1. Univ. of Missouri, Columbia (USA)

Glyoxysomal malate synthase (MS) was purified to apparent homogeneity from 3-d germinating castor oil seed endosperm by a relatively simple procedure including two sucrose density gradient centrifugations. Antibodies raised to the caster oil seed MS crossreacted with MS from cucumber cotyledon. MS was phosphorylated in both tissues in an MgATP dependent reaction. The phosphorylation pattern was similar for both enzymes and both enzymes were inhibited by NaF, NaMo, (NH{sub 4})SO{sub 4}, glyoxylate and high concentration of MgCl{sub 2} (60 mM), but was not inhibited by NaCl and malate. Further characterization of the phosphorylation of MS from castor oil seed endosperms showed that the 5S form of MS is the form which is labelled by {sup 32}P. The addition of exogenous alkaline phosphatase to MS not only decreased enzyme activity, but could also dephosphorylate phospho-MS. The relationship between dephosphorylation of MS and the decrease of MS activity is currently under investigation.

• OSTI ID: 6611070
• Journal Information: Plant Physiology, Supplement; (USA), Journal Name: Plant Physiology, Supplement; (USA) Vol. 89:4; ISSN PPYSA; ISSN 0079-2241
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ALKALINE PHOSPHATASE
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
CASTOR
CHEMICAL REACTIONS
CUCUMBERS
DAYS LIVING RADIOISOTOPES
ENZYME ACTIVITY
ENZYME INHIBITORS
ENZYMES
ESTERASES
EUPHORBIA
FOOD
FRACTIONATION
HYDROLASES
ISOTOPE APPLICATIONS
ISOTOPES
LIGHT NUCLEI
LYASES
MAGNOLIOPHYTA
MAGNOLIOPSIDA
MEDICINAL PLANTS
NUCLEI
ODD-ODD NUCLEI
PHOSPHATASES
PHOSPHORUS 32
PHOSPHORUS ISOTOPES
PHOSPHORYLATION
PLANTS
RADIOISOTOPES
SEPARATION PROCESSES
TRACER TECHNIQUES
VEGETABLES