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N Kh Mekhtiev

Publications and source records attributed to N Kh Mekhtiev.

11 recordsLinked to original sources
PubMed1983

[Affinity chromatography and properties of cGMP-dependent protein kinase from prawn tissues].

Using affinity chromatography on 8-(2-aminoethyl)-amino-cAMP Sepharose, the cGMP-dependent protein kinase (ATP: protein phosphotransferase, EC 2.7.1.37) from tissues of the prawn Palaemon adspersus was purified to homogeneity as demonstrated by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate. The degree of enzyme purification was 11 200, recovery--6.5%; the isoelectric point for the enzyme lies at 5.5. Data from gel filtration and centrifugation in sucrose density gradient suggest that the dimer of cGMP-dependent protein kinase has a molecular weight of 157 000, sedimentation coefficient of 7.2S and a Stokes' radius of 50 A. An active form of the enzyme with Mr = 76 500 (4.5S, 39 A) which apparently represents a subunit of the cGMP-dependent protein kinase was discovered. The activity of the both enzyme forms are stimulated by low concentrations of cGMP (Ka = 1.10(-7) M). The monomer and dimer molecules appear as prolate ellipsoids with axial ratios close to 7. The native cGMP-dependent protein kinase is probably made up of two subunits each of which contains a regulatory and a catalytic sites.

Animals↗
PubMed1982

[Partial purification and properties of cGMP-dependent protein kinase from prawn tissue].

Using ion-exchange chromatography and gel filtration, cGMP-dependent protein kinase was purified from prawn tissues 220-fold with a yield of activity of 12%. The apparent Ka values for cGMP, cAMP and 8-Br-cGMP are 1 . 10(-7), 5 . 10(-6) and 5 . 10(-8) M, respectively; the apparent Km values for ATP in the presence of cGMP is 9 . 10(-6) M. The cGMP-stimulated protein kinase activity was observed only in the presence of SH-compounds and high Mg2+ concentrations (500-100 mM). The protein kinase demonstrated a broad pH optimum wih a maximum at pH 6.8-7.2. The elution volume of the enzyme during gel filtration corresponded to a globular protein with molecular weight of 140,000.

Animals↗
PubMed1981

[Protein modulator of cyclic nucleotide-dependent protein kinases from the shrimp Palaemon adspersus].

A thermostable protein modulator of cyclic nucleotide-dependent protein kinases was isolated and purified from the tissue of the shrimp Palaemon adspersus. The molecular weight, N-terminal amino acid and amino acid composition of the protein modulator were determined and its effects on cAMP-dependent protein kinase depending on substrate and cation concentrations were investigated. The protein modulator under study is a low molecular weight (15 000) acid protein, pI-435, which exerts both strong activating and inhibitory effects on cAMP-dependent protein kinase in the reactions of phosphorylation of protamine and histones, respectively.

Amino Acids↗
PubMed1980

[Effect of sodium selenite on RNA synthesis in loach embryos].

The effects of sodium selenite on the ribonucleic acid synthesis in normal diploid embryos and isolated nuclei of the loach Misgurnus fossilis were studied. The relative rate of synthesis was determined from incorporation of [3H]uridine into the total RNA, taking into consideration the incorporation of the label into the total acid-soluble fraction and into phosphorylated derivatives of uridine. It was shown that sodium selenite inhibits the RNA synthesis in loach embryos at the gastrula stage. It was also found that sodium selenite exerts an inhibiting effect on the activity of form I of DNA-dependent RNA-polymerase in isolated loach nuclei without affecting the activity of the enzyme form II.

Animals↗
PubMed1975

[Biochemical genetics of erythrocyte arylesterase in karakul sheep].

Three zones of esterase activity were established in zymograms of erythrocyte lysates in karakul sheep by means of starch gel electrophoresis. These zones were distinguished according to their substrate specificity and inhibition tests and desnguated as arylesterase (I), carbonic anhydrase (II) and aliesterase (III). The following phenotypes of erythrocyte arylesterase were distinguished in the two populations of karakul sheep studied: AEs - A, AEs - AB, AEs - AC, AEs - AD, AEs - B, AEs - BC, AEs - BD, AEs - C, AEs - CD, AEs - D. These phenotypes are controlled by 4 dominant alleles, VIZ. AEsA, AEsB, AEsC, AEsD. Gene frequencies vary from population to population: from 0.012 +/- 0.005 to 0.118 +/- 0.027, from 0.331 +/- 0.021 to 0.340 +/- 0.012, from 0.601 +/- 0.022 to 0.250 +/- 0.011 and from 0.056 +/- 0.003 to 0.292 +/- 0.011 for AEsA, AEsB, AEsC and AEsD respectively. The actually observed distribution of arylesterase phenotypes is in accordance with the theoretically expected values (p is less than 0.95).

Alleles↗
PubMedDate not supplied

[Pneumatic micropipette].

Plunger micropipettes commonly used in medicine, biology and virology have low accuracy, a narrow dose measuring range, and their manufacture, adjustment and servicing are labor-consuming processes. In this article the working principle of a pneumatic micropipette is analyzed. The elements of industrial pneumoautomatic equipment are shown to give the possibilities for realizing not only all the main functions of plunger micropipettes, but also some additional functions which cannot be performed by plunger pipettes. The design and working principles of a single-channel pneumatic micropipette are described. Pneumatic micropipettes are shown to have essential advantages over plunger micropipettes in the main technical characteristics, e. g. accuracy, a dose measuring range, operating convenience, etc.

Equipment and Supplies↗