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Title: Relationship between 5S and 20S forms of malate synthase in maturing cottonseeds

Malate synthase (MS) activity appears and increases during seed maturation persists during desiccation, then increases again following germination. Because different modes of synthesis and organelle import of MS may occur in maturing and germinated seeds, a comparative study was performed. A comparison of immunoprecipitations from in-vivo-labeled seeds (/sup 35/S-met) and in-vitro translations of Poly A+ RNA (wheat germ) showed no detectable differences in subunit mol wt. When MS activity first appears (42 DPA) only the cytosolic 5S form is found in rate-zonal gradients (5-25% sucrose). At 48 DPA, O d, and 48 h germinated seeds both the 5S and glyoxysomal 20S forms are present, with the 20S becoming more prevalent. Western blots of SDS-PAGE gels showed that no other form(s) of MS (inactive) are present in rate-zonal fractions. Calculations of radiospecific activity (per MS activity) of 5S and 20S forms radiolabeled in vivo (/sup 35/S-met) at various time periods provided further convincing evidence that there is a 5S precursor to 20S product relationship during both seed maturation and seedling growth.
Authors:
;
Publication Date:
OSTI Identifier:
5903871
Report Number(s):
CONF-8707108-
Journal ID: CODEN: PPYSA; TRN: 87-037217
Resource Type:
Conference
Resource Relation:
Journal Name: Plant Physiol., Suppl.; (United States); Journal Volume: 83:4; Conference: Annual meeting of the American Society of Plant Physiologists, St. Louis, MO, USA, 19 Jul 1987
Research Org:
Arizona State Univ., Tempe
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES; LIGASES; BIOSYNTHESIS; MOLECULAR WEIGHT; PRECURSOR; SEEDS; ENZYME ACTIVITY; CENTRIFUGATION; COTTON PLANTS; ELECTROPHORESIS; GERMINATION; HYBRIDIZATION; IMMUNOASSAY; LABELLED COMPOUNDS; METHIONINE; ORGANOIDS; PLANT GROWTH; RNA; SEDIMENTATION; SEEDLINGS; SULFUR 35; TRACER TECHNIQUES; TRANSLOCATION; WHEAT; AMINO ACIDS; BETA DECAY RADIOISOTOPES; BETA-MINUS DECAY RADIOISOTOPES; CARBOXYLIC ACIDS; CELL CONSTITUENTS; CEREALS; DAYS LIVING RADIOISOTOPES; DRUGS; ENZYMES; EVEN-ODD NUCLEI; GRASS; GROWTH; ISOTOPE APPLICATIONS; ISOTOPES; LIGHT NUCLEI; LIPOTROPIC FACTORS; NUCLEI; NUCLEIC ACIDS; ORGANIC ACIDS; ORGANIC COMPOUNDS; ORGANIC SULFUR COMPOUNDS; PLANTS; RADIOISOTOPES; SEPARATION PROCESSES; SULFUR ISOTOPES; SYNTHESIS 550201* -- Biochemistry-- Tracer Techniques