Cation-induced formation of a macro-glucan synthase complex

Conference · Tue May 01 04:00:00 EDT 1990 · Plant Physiology, Supplement; (USA)

OSTI ID:5851316

Delmer, D; Solomon, M; Andrawis, A; Amor, Y ^[1]

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1. Hebrew Univ., Jerusalem (Israel)

Incubation of Chaps or digitonin-solubilized membrane proteins from cotton fiber with Ca{sup 2+} in combination with Mg{sup 2+}, leads to formation of a complex which can be sedimented within 15 min at 15,000 g. The complex is enriched >10-fold in callose synthase activity and possesses a characteristic pattern of enriched polypeptides when analyzed by SDS-PAGE. Although cation dependent, formation of the complex is not dependent upon the presence of the callose synthase substrate, UDP-glc, indicating that complex formation is not due to entrapment of the enzyme by association with glucan product. The enriched polypeptides include: >200, 50, and 46 kD, all of which have been shown by direct photo-labeling to interact with {sup 92}P-UDP-glc in a Ca{sup 2+} or beta-glucoside dependent reaction are considered likely subunits of callose synthase; a 60-62 kD doublet which is recognized by our MAb 2-1 which can form an immune complex with callose synthase; 74 and 34 kD polypeptides which also interact with UDP-glc, but do not associate with callose synthase in the presence of EDTA. A similar phenomenon is also observed with solubilized membrane proteins from mung beans. Possible functions of each of the enriched polypeptides, the catalytic properties, and ultra-structure of this macro-glucan synthase complex are currently under investigation.

• OSTI ID: 5851316
• Report Number(s): CONF-9007196--
• Conference Information: Journal Name: Plant Physiology, Supplement; (USA) Journal Volume: 93:1
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ALKALINE EARTH METALS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOCHEMICAL REACTION KINETICS
CALCIUM
COTTON
DAYS LIVING RADIOISOTOPES
ELEMENTS
ENZYMES
ISOTOPE APPLICATIONS
ISOTOPES
KINETICS
LIGHT NUCLEI
MAGNESIUM
METALS
NUCLEI
ODD-ODD NUCLEI
PHOSPHORUS 32
PHOSPHORUS COMPOUNDS
PHOSPHORUS ISOTOPES
RADIOISOTOPES
REACTION KINETICS
SYNTHESIS
TRACER TECHNIQUES