An analysis of residual stresses in the basic cutting process

Imperial Users onl

Axial control of protein reserve mobilization during germination of indian bean (Dolichos lablab L.) seeds

The influence of embryonic axis and exogenously applied plant growth hormones on protein mobilization and development of proteases have been investigated in Indian bean (Dolichos lablab L. var lignosus) seeds during germination and post-germinative growth up to 10 days. Accumulation of free amino acids synchronized with rapid proteolysis and higher levels were maintained throughout the germination period. The presence of proteases (acid, neutral and alkaline) with three different pH optima increased in the early stages of germination and decreased later. The axis-excision affected the activities of proteases and protein degradation. Furthermore, the free amino acid content increased continuously in detached cotyledons throughout the germination period. Treatment with 1% casein hydrolysate to simulate the accumulation of free amino acids had a telling inhibitory effect on the proteases in attached and detached cotyledons. Exogenously applied phytohormones BA (Benzyl adenine), GA3 (Gibberellic acid) or IAA (Indole acetic acid) resulted in stimulation of development of proteases as well as proteolysis in detached cotyledons. The two hypotheses, source-sink and hormonal stimulus both were influencing in the mobilization of food reserves and the growth of seedling. The results of the study supports the role of axis in protein mobilization regulating the development of proteases by providing phytohormone signals and regulation of their activity in vivo by a feedback mechanism

Purification of acidic protease from the cotyledons of germinating Indian bean (Dolichos lablab L. var lignosus) seeds

The positive correlation between the developments of acid, neutral and alkaline proteases (azocaseinolytic) with protein depletion suggest the involvement of these proteases in the degradation of proteins in germinating Indian bean. These proteases increased in the early stages of germination and decreased later. However, the activity of acid proteases was higher throughout the germination period compared with the activities of neutral and alkaline proteases. The acid protease from the cotyledons of 4-day old germinating Indian bean seedlings was purified to 152 folds by a five step procedure comprising - crude extract from cotyledons, (NH4)2SO4 fractionation, DEAE-cellulose, CM-cellulose and finally casein-agarose affinity chromatography. The molecular mass of acidic protease is 32 kDa.African Journal of Biotechnology Vol. 4 (7), pp. 703-707, 200

Purification and characterization of cysteine protease from germinating cotyledons of horse gram

<p>Abstract</p> <p>Background</p> <p>Proteolytic enzymes play central role in the biochemical mechanism of germination and intricately involved in many aspects of plant physiology and development. To study the mechanism of protein mobilization, undertaken the task of purifying and characterizing proteases, which occur transiently in germinating seeds of horse gram.</p> <p>Results</p> <p>Cysteine protease (CPRHG) was purified to homogeneity with 118 fold by four step procedure comprising Crude extract, (NH4)2SO4 fractionation, DEAE-Cellulose and CM-sephacel chromatography from the 2 day germinating cotyledons of horse gram (<it>Macrotyloma uniflorum </it>(Lam.) Verdc.). CPRHG is a monomer with molecular mass of 30 k Da, was determined by SDS-PAGE and gel filtration. The purified enzyme on IEF showed two isoforms having pI values of 5.85 and 6.1. CPRHG composed of high content of aspartic acid, glutamic acid and serine. The enzyme activity was completely inhibited by pCMB, iodoacetate and DEPC indicating cysteine and histidine residues at the active site. However, on addition of sulfhydryl reagents (cysteine, dithiothreitol, glutathione and beta-ME) reverse the strong inhibition by pCMB. The enzyme is fairly stable toward pH and temperature. Immunoblot analysis shows that the enzyme synthesized as zymogen (preproenzyme with 81 kDa) and processed to a 40 kDa proenzyme which was further degraded to give 30 kDa active enzyme.</p> <p>Conclusion</p> <p>It appears that the newly synthesized protease is inactive, and activation takes place during germination. CPRHG has a broad substrate specificity and stability in pH, temperature, etc. therefore, this protease may turn out to be an efficient choice for the pharmaceutical, medicinal, food, and biotechnology industry.</p