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The nitrate reductase stabilizing factor in cotton seeds
Author(s) -
PURVIS ALBERT C.,
TISCHLER CHARLES R.,
FUNKHOUSER EDWARD A.
Publication year - 1980
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.1980.tb03274.x
Subject(s) - nitrate reductase , trypsin , germination , casein , protease , phosphate , biochemistry , stabilizer (aeronautics) , chemistry , dehydrogenase , nitrate , trypsin inhibitor , reductase , enzyme , biology , botany , organic chemistry , mechanical engineering , engineering
A heat‐stable factor present in dry cotton ( Gossypium hirsutum L.) seed, or in cotyledons until day 4 of germination, is capable of stabilizing labile nitrate reductase from other species. The stabilizing factor has no effect on stability of glyceralde‐hyde‐3‐phosphate dehydrogenase, but slightly improves the stability of glucose‐6‐phosphate dehydrogenase. Treatment with protease III, and to a lesser extent, trypsin, reduces the effectiveness of the stabilizer. The stabilizer is not a trypsin inhibitor. Dialysis demonstrates that the stabilizing factor has a molecular weight greater than 12,000 daltons. The factor precipitates between 25 and 75% (NH 4 ) 2 SO 4 saturation, and is effective at protein concentrations much lower than those required when casein is employed. – From the results of this study, we conclude that the factor which stabilizes labile nitrate reductase from cotton seed is proteinaceous.