Aleksandr Osipenko

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The HEN1 methyltransferase from Arabidopsis thaliana modifies the 3'-terminal nucleotides of small regulatory RNAs. Although it is one of the best characterized members of the 2'-O-methyltransferase family, many aspects of its interactions with the cofactor and substrate RNA remained unresolved. To better understand the substrate interactions and(More)
It is established tha in skeletal muscles of dormant animals under the influence of training the 3':5'-AMP content and the activity of adenylate cyclase increase; that of phosphodiesterase remains unchanged. A long physical load causes no changes in the 3':5"-AMP content in the skeletal muscles of the trained rats as compared to its content in the intact(More)
During 6-week training of rats the activity of isoenzymes I and II of soluble 3':5'-AMP-dependent protein kinase increases by 22 and 33%, respectively. A long-term physical load does not cause any significant changes in the activity of both isoenzymes. The maximal activity of the isoenzymes from skeletal muscles of the control and experimental rats is(More)
Three fractions of rat adenosine-3',5'-monophosphate-dependent protein kinase were isolated, partially purified in buffer concentration gradient at normal state and after long-term physical loading and studied. It is found that first two fractions of protein kinases at normal state and after intensive muscular work have similar activities with and without(More)
The purified membrane fragments of sarcoplasmic reticulum (SR) of rabbit fast skeletal muscles were found to incorporate 32P from[gamma-32P]ATP in endogenous membrane substrates and in histone H1. The existence of membrane-bound protein kinase of SR was demonstrated by steady state binding of [3H]-cAMP to the SR membranes. The constant of [3H]cAMP binding(More)
MicroRNAs regulate gene expression in numerous biological pathways and are typically methylated at their 3'-termini in plants but not in animals. Here we show that the HEN1 RNA 2'-O-methyltransferase from Arabidopsis thaliana catalyzes the transfer of extended propargylic moieties from synthetic AdoMet cofactor analogs to duplex miRNAs or siRNAs. The(More)
Myometrium of female rabbits at the state of functional rest contained 260 pmoles of cAMP per g of tissue and 25 pmoles cGMP. In dynamics of pregnancy content of cAMP was increased up to 400 pmoles/g within the second half of pregnancy; the content of cGMP was decreased down to 10 pmoles/g. During labor content of cAMP and of cGMP became minimal; within the(More)
Two forms of soluble phosphodiesterase of cyclic nucleotides separating by DEAE-cellulose ion-exchange chromatography and not only differing in physicochemical and catalytic parameters but also differently regulated by calmodulin are found in the doe myometrium. Calmodulin with 10(-7)-10(-5) M concentrations of Ca2+ promotes the two-fold activation of the(More)
Highly purified plasma membrane (PM) preparations of pig myometrium were found to contain 0.91 +/- 0.22 microgram calmodulin per mg of PM protein. Treatment of membranes with 1 mM EGTA in the presence of 0.2 M NaCl causes the diminution of the calmodulin content down to 3% of the original level. The activity of Ca, Mg-ATPase is thereby decreased by 40%.(More)
Separation of phosphorylated sarcoplasmic reticulum (SR) fragments by polyacrylamide gel disc electrophoresis in the presence of Na-DS revealed that the radioactivity is distributed in protein zones with molecular weights of 95,000 and 6000-8000. The phosphorylation of the protein with m. w. of 95,000 is Ca2+-dependent. The tryptic hydrolysis of the(More)