RESUMEN
The soluble complexes of stellins A and B-protamines from Acipenser stellatus-with DNA were obtained by direct mixing in 2,5.10(-4) M EDTA, pH 8,0. The differential curves of melting of the complexes reveal two transitions at Tmelt.1=49+/-1 degree and Tmelt.2=90+/-1 degree, corresponding to melting of DNA regions of free and protamine-bound DNA regions. The number of amino acid residues per one nucleotide in the protein-binding sites of DNA is 1,30 and 1,22 for the stellin A- and stellin B-DNA complexes, respectively. It was demonstrated that under denaturation the DNA filaments do not break apart completely. Data from the analysis of products of the complexes hydrolysis by DNAse I allowed to postulate a selective binding of the protamines to the AT-pairs of DNA. This assumption was confirmed by changes in the melting curves under different protein/DNA ratios.
Asunto(s)
ADN , Desoxirribonucleasas , Endonucleasas , Proteínas de Peces , Protaminas , Animales , Desoxirribonucleasa I , Peces , Cinética , Desnaturalización de Ácido Nucleico , Unión Proteica , TemperaturaRESUMEN
After a single intravenous administration of sturines A and B into rats subjected to partial hepatectomy, during the periods, corresponding to maximal synthesis of DNA, incorporation of 3H-thymidine into nuclear DNA was decreased by 20-30% and incorporation into mitochondrial DNA--by 40-50%, as compared with control. The treatment with sturines led to distinct decrease in activity of nuclear thymidine kinase and ribonucleotide reductase but did not affect the enzymatic activity in mitochondria. The sturine preparations (at concentrations 10(-6)--10(-3) M) inhibited the activity of these enzymes (of both nuclear and mitochondrial origin) in vitro.
Asunto(s)
ADN/biosíntesis , Hígado/metabolismo , Ribonucleótido Reductasas/antagonistas & inhibidores , Timidina Quinasa/antagonistas & inhibidores , Animales , Núcleo Celular/enzimología , ADN Mitocondrial/biosíntesis , Masculino , Mitocondrias Hepáticas/metabolismo , Ratas , Timidina/metabolismoRESUMEN
A possibility to fractionate fibrinolytically and thrombolytically active complex "tricholysin" into five components, differing in iso-points and in enzymatic activity, is demonstrated by means of isoelectric focusing using ampholine solution within pH range 3.0-10.0. Homogenous fraction IV (isopoint 6.8-7.0) has a low caseinolytic activity and a high specific fibrinolytic and esterase activities. This fraction is characterized with a high ability of plasminogen activation. Serine, threonine, alanine and valine are found to prevail in amino acid composition of the fraction IV, its molecular weight being 39000.
Asunto(s)
Enzimas/aislamiento & purificación , Fibrinolíticos/aislamiento & purificación , Aminoácidos/análisis , Fenómenos Químicos , Química , Esterasas/aislamiento & purificación , Focalización Isoeléctrica , Hongos Mitospóricos , Peso Molecular , Péptido Hidrolasas , Activadores Plasminogénicos/aislamiento & purificaciónRESUMEN
A preparation of fibrinolytic enzymes that produced a specific effect on blood fibrinolysis in animals was isolated from the culture liquid filtrate of the fungus Trichothecium roseum. By gel filtration on KM-Sephadex G-50 six fractions differing in their fibrinolytic, esterase and caseinolytic activities were obtained. The most effective fibrinolytic agents were the first and fourth fractions that had high fibrinolytic and esterase activities and a low caseinolytic activity.