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CaCl2 Concentration (cacl2 + concentration)
Selected AbstractsSynthesis and Characterization of Thrombin Conjugated ,-Fe2O3 Magnetic Nanoparticles for HemostasisADVANCED ENGINEERING MATERIALS, Issue 12 2009Ofra Ziv Abstract Thrombin is the final protease produced in the clotting pathways. Thrombin has been used in the clinic more than six decades for topical hemostasis and wound management. In human plasma the half-life of thrombin is shorter than 15 seconds due to close control by inhibitors. In order to stabilize thrombin, this enzyme was conjugated covalently and physically to ,-Fe2O3 magnetic nanoparticles. The physical conjugation was accomplished through adsorption of thrombin to BSA coating on the nanoparticles. The coagulant activity of the covalently bound thrombin was significantly lower than that of the physically adsorbed thrombin. Leakage of the physically bound thrombin into PBS containing 4% HSA was negligible. The physical conjugation of thrombin onto the nanoparticles stabilized the thrombin against its major inhibitor antithrombin III and improved its storage stability. At optimal CaCl2 concentration, the clotting time by the bound thrombin is shorter than that of the free enzyme. This novel conjugated thrombin may be an efficient candidate for topical hemostasis and wound healing. [source] PROTEINASES IN HYBRID CATFISH VISCERA: CHARACTERIZATION AND EFFECT OF EXTRACTION MEDIAJOURNAL OF FOOD BIOCHEMISTRY, Issue 4 2010SAPPASITH KLOMKLAO ABSTRACT Proteolytic activity from viscera extract of hybrid catfish (Clarias macrocephalus × Clarias gariepinus) was investigated. Optimal pH and temperature for casein hydrolysis were 9.0 and 50C, respectively. The enzyme was stable to heat treatment up to 40C and over a pH range of 7,11 for 30,120 min. The proteolytic activity was effectively inhibited by soybean trypsin inhibitor, benzamidine, phenylmethylsulfonyl fluoride and N -p-tosyl-L-lysine chloromethyl ketone. Activities of the viscera extract continuously decreased as NaCl concentration increased, while activities increased as CaCl2 concentration increased. Based on the proteinase activity of zones separated by electrophoresis, the molecular mass of the major proteinases in hybrid catfish viscera was 23 and 20 kDa. The effect of extraction media on recovery of proteinases was also studied. Extraction of the viscera powder with 50 mM Tris-HCl, pH 7.0 containing 0.5 M NaCl and 0.2% (v/v) Brij 35 rendered a higher recovery of proteinase activity than other extractants tested (P < 0.05). The results suggested that major proteinases in hybrid catfish viscera were heat-activated alkaline proteinases, most likely trypsin-like serine proteinases. PRACTICAL APPLICATIONS Hybrid catfish viscera is an abundant and underutilized resource that can be used as a unique proteinase source. Proteinase from various sources catalyzes the hydrolysis of peptide bonds. Thus, it is expected that like other proteinases, hybrid catfish proteinase would be useful in biomedical, food and beverage application. Moreover, the presented extraction media could be adopted to recover the trypsin-like serine proteinase from hybrid catfish viscera, which is currently a solid waste of Pa-duk-ra industry. [source] COMPARATIVE STUDIES ON PROTEOLYTIC ACTIVITY OF SPLENIC EXTRACT FROM THREE TUNA SPECIES COMMONLY USED IN THAILANDJOURNAL OF FOOD BIOCHEMISTRY, Issue 5 2004SUPPASITH KLOMKLAO ABSTRACT Proteolytic activities of splenic extract from three tuna species including skipjack tuna (Katsuwonus pelamis), yellowfin tuna (Thunnus albacores) and tongol tuna (Thunnus tonggol) were studied. Optimal activity of splenic extract from all tuna species was at pH 9.0 and 55C when casein was used as a substrate. Among all species tested, yellowfin tuna showed the highest activity, followed by skipjack tuna and tongol tuna. The proteolytic activity was strongly inhibited by soybean trypsin inhibitor, TLCK and partially inhibited by ethylenediaminetetraacetic acid. E-64, N-ethylmaleimide, iodoacetic acid, TPCK and pepstatin A showed no inhibition. The effect of NaCl and CaCl2 on proteolytic activity was also investigated. Activities continuously decreased as NaCl concentration increased, and no activity remained in the presence of 30% NaCl. On the other hand, activities increased as CaCl2 concentration increased. The highest activity was obtained in the presence of 1 mM CaCl2. SDS-substrate gel electrophoresis revealed that major proteinases in splenic extract from different tuna species were different in apparent molecular weights and sensitivity to TLCK. Although the major activity bands of all species were strongly inhibited by soybean trypsin inhibitor, varying sensitivity to TLCK probably implied the differences in binding characteristic of enzyme to substrate and/or inhibitors. The results suggest that major proteinases in spleen of all tuna species were trypsin-like serine proteinases. [source] Formation of Soy Protein Isolate Cold-set Gels: Protein and Salt EffectsJOURNAL OF FOOD SCIENCE, Issue 1 2005Anne Maltais ABSTRACT: The influence of protein and calcium concentration on soy protein cold-set gel formation and rheology has been investigated. Cold-set gels can be formed at soy protein concentrations from 6% to 9% and calcium concentrations from 10 to 20 mM. Gel properties can be modulated by changing the protein and/or CaCl2 concentrations. An increase in CaCl2 concentration from 10 to 20 mM increased gel opacity while an increase in protein concentration from 6% to 9% decreased opacity. Water-holding capacity improved with increasing protein concentration and decreasing CaCl2 concentration. The elastic modulus (G') increased with protein and calcium chloride concentrations. Microscopy revealed an increase in the diameters of aggregates and pores as CaCl2 concentration increased and as protein concentration decreased. Cold-set gels with a broad range of characteristics can be obtained from soy protein. [source] | ||||||||||