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Data on the physico-chemical properties of proteins from soybean, groundnut, sesame seed, sunflower seed, safflower seed,
mustard seed, rapeseed and cotton seed are fairly extensive. An examination of the available data on high molecular weight
proteins suggests that there are similarities in many of their properties. In this report the similarity in amino acid composition,
size and shape, molecular weight, secondary structure, subunit composition, association-dissociation at high and low pH, stability
towards denaturants, hydrolysis by enzymes and quaternary structure of the high molecular weight proteins is discussed. Based
on these similarities a model has been proposed for the associationdissociation, denaturation and reassociation behaviour
of the high molecular weight proteins of oilseeds. 相似文献
2.
The effect of a decrease inpH on the structural integrity of carmin has been monitored by a variety of biophysical techniques. The protein undergoes initial dissociation up topH 3.5–4.0 without any significant denaturation. Below thispH the process of dissociation and denaturation appears to be simultaneous. Further, in thepH range of 2.5–1.6 the protein reassociates to probably a different polymer resulting from possibly, an entropically driven hydrophobic interaction. The process of dissociation appears to be reversible to a large extent. The process of denaturation appears to be governed by the kinetic path that the denatured protein molecule follows either by a sudden decrease inpH or through a gradual decrease inpH. These results are interpreted while keeping in view the oligomeric and globular structure of carmin at neutralpH. The results would help in understanding of structure-function relationship of the protein and its role in hydrogen ion bindingin vivo. 相似文献
3.
The electrophoretic pattern of o-diphenolase multiple forms was significantly altered in auxin (2,4-D)-treated embryos, although there was no appre 相似文献
4.
Aspartate transcarbamylase (EC 2.1.3.2) was purified to homogeniety from germinated mung bean seedlings by treatment with
carbamyl phosphate. The purified enzyme was a hexamer with a subunit molecular weight of 20,600. The enzyme exhibited multiple
activity bands on Polyacrylamide gel electrophoresis, which could be altered by treatment with carbamyl phosphate or UMP indicating
that the enzyme was probably undergoing reversible association or dissociation in the presence of these effectors. The carbamyl
phosphate stabilized enzyme did not exhibit positive homotropic interactions with carbamyl phosphate and hysteresis. The enzyme
which had not been exposed to carbamyl phosphate showed a decrease in specific activity with a change in the concentration
of both carbamyl phosphate and protein. The carbamyl phosphate saturation and UMP inhibition patterns were complex with a
maximum and a plateau region. The partially purified enzyme also exhibited hysteresis and the hysteretic response, a function
of protein concentration, was abolished by preincubation with carbamyl phosphate and enhanced by preincubation with UMP. All
these observations are compatible with a postulation that the enzyme activity may be regulated by slow reversible association-dissociation
dependent on the interaction with allosteric ligands 相似文献
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