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An improved method for purification of L-threonine deaminase from rat liver
No full textL-threonine deaminase was obtained at a high degree of purity from rat liver. Two main steps were added to the previously reported procedure: cryoprecipitation and chromatofocusing (in the presence of a specific KCl concentration). The purification factor was 3,090 and the specific activity 989. The method is very reproducible and convenient. It gives the highest specific activity and the highest degree of purity of the enzyme recorded to date
In Vitro Regulation of Rat Liver L-Threonine Deaminase by different effectors
No full textThe regulation of liver L-threonine deaminase by different effectors--bile acids, bile pigments and monocarbon molecules--was investigated. Total inhibition of the enzyme was observed with physiological concentrations of bile acids and biliverdin. Purely competitive inhibition of the holoenzyme by several monocarbon molecules was demonstrated; the mechanism was partially competitive for bicarbonate. Inhibition was more pronounced in the case of the dialyzed enzyme. From the higher Km values for pyridoxal-5'-phosphate (PLP), obtained in the presence of the inhibitors, the results are explained on the basis of interference in the association reaction: apoprotein + PLP----holoenzyme. The various effects determined by bicarbonate may play a specific role in vivo since they occur at physiological concentrations of this compound
Determination of Vascular Endothelium Growth Factor by Elisa Test and comparison with Western Blot
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Ultrastructural and biochemical investigations of protein mobilization of Mucuna pruriens (L.) DC cotyledons and embryo axis.
No full textThe mobilization of storage reserves, with particular emphasis on storage proteins of Mucuna pruriens (L.) DC., cotyledons, and embryo was investigated from the ultrastructural and biochemical points of view. Proteins and starch were the two main storage substances in cotyledons, and proteins and lipids were the main ones in the embryo. Embryo protein bodies were smaller and fewer in number than those of cotyledons. Structural and ultrastructural data determined between 24 and 48 h after imbibition and between 48 and 72 h after imbibition, the end of significant embryo and cotyledon protein mobilization, respectively, indicating more precocious storage protein mobilization in the axis than cotyledons. Moreover, storage protein mobilization in embryo and cotyledons occurred before the end of germination. Water soluble proteins were separated by sodium dodecyl sulfate polyacrylamide gel electrophoresis, producing 29 bands with molecular weights from 14 to 90 KDa. Embryo extract contained more proteins than cotyledon extract, contained seven characteristic bands, and showed a higher variability of the optical density trend than cotyledon
Determination of Urinary Methylated Purine Pattern by High Performance Liquid Chromatography
No full textWe describe the group selective separation and quantification of unmodified and modified purines in human urine by high-performance reverse phase liquid chromatography. The pattern of oxypurines and methylated purines: hypoxanthine (Hx), xanthine (X), 1-methyl hypoxanthine (1-MHx), 1-methyl guanine (1-MG), 3-methyl guanine (3-MG), 7-methyl guanine (7-MG), 1-methyl xanthine (1-MX), 3-methyl xanthine (3-MX), 7-methyl xanthine (7-MX), 1,7-dimethyl guanine (1,7-dMG), 1,3-dimethyl xanthine (1,3-dMX), 1,7-dimethyl xanthine (3,7-dMX) and 1,3,7-trimethyl xanthine (1,3,7-tMX) were determined in a single run in urine of a healthy subject and a gout patient before and after treatment with allopurinol. This method may be useful to investigate the urinary pattern of methylated bases in diseases involving purine metabolism
Biological Role of Carbamoyl pyridoxal 5'-phosphate
No full textA new compound, carbamoyl-pyridoxal 5'-phosphate (C-PLP), was synthetized by condensation of pyridoxal 5'-phosphate (PLP) with KCNO. It may be obtained under certain physiological conditions of pH, temperature and concentration of reagents. Formation and degradation of C-PLP are readily reversible chemical reactions, not involving enzymes, at least in rat tissues. However, different considerations suggest that synthesis and breakdown of C-PLP play a biological role in the cell, providing 'protective synthesis' and a 'variable reservoir' of PLP and KCNO, which can be trapped by other proteins, apoenzymes and metabolites, to regulate many cell metabolic functions
Effects of snake venom proteases on human fibrinogen chains
No full textProteomic approach is an effective method to study changes in human plasma proteome. Coagulopathies are commonly encountered in victims of viper envenomation which were treated with an administration of immunoglobulin. Unfortunately, this treatment shows significant risk to the patient due to an anaphylactic reaction. Since Echis carinatus Venom (EV) toxins mainly acts both directly and indirectly on fibrinogen, we planned to establish a suitable analysis of its beta (FIBB) e gamma (FIBG) chains. This study will help us to understand the mechanism of envenomation and to find alternative treatments other than the common treatment with the administration of IgG
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