Peeter Sikk
Estonian Academy of Sciences
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Featured researches published by Peeter Sikk.
Molecular and Cellular Biochemistry | 1998
Valdur Saks; Vladimir Veksler; Andrei V. Kuznetsov; Laurence Kay; Peeter Sikk; Toomas Tiivel; Leone Tranqui; Jose Olivares; Kirstin Winkler; Falk R. Wiedemann; Wolfram S. Kunz
In this chapter we describe in details the permeabilized cell and skinned fiber techniques and their applications for studies of mitochondrial function in vivo. The experience of more than 10 years of research in four countries is summarized. The use of saponin in very low concentration (50–100 μg/ml) for permeabilisation of the sarcolemma leaves all intracellular structures, including mitochondria, completely intact. The intactness of mitochondrial function in these skinned muscle fibers is demonstrated in this work by multiple methods, such as NADH and flavoprotein fluorescence studies, fluorescence imaging, confocal immunofluorescence microscopy and respiratory analysis. Permeabilized cell and skinned fiber techniques have several very significant advantages for studies of mitochondrial function, in comparison with the traditional methods of use of isolated mitochondria: (1) very small tissue samples are required; (2) all cellular population of mitochondria can be investigated; (3) most important, however, is that mitochondria are studied in their natural surrounding. The results of research by using this method show the existence of several new phenomenon — tissue dependence of the mechanism of regulation of mitochondrial respiration, and activation of respiration by selective proteolysis. These phenomena are explained by interaction of mitochondria with other cellular structures in vivo. The details of experimental studies with use of these techniques and problems of kinetic analysis of the results are discussed. Examples of large-scale clinical application of these methods are given. (Mol Cell Biochem 184: 81–100, 1998)
Biochimica et Biophysica Acta | 1999
Tuuli Kaambre; Vello Tõugu; Peeter Käämbre; Heiki Vija; Peeter Sikk
Hydrolysis of the emulsified mixture of short-chain triacylglycerols by porcine pancreatic lipase in the presence of procolipase and micellar sodium taurodeoxycholate has been studied. Increase in the content of tributyrin and trioctanoin in the mixture with triacetin had highly cooperative effects on the formation of the interfacial lipase procolipase complex. Abrupt enhancement of the complex stability was observed in the presence of 0.4-0.6 mol mol-1 of tributyrin or 0.58 mol mol-1 of trioctanoin in the substrate phase. The affinity of lipase towards interfacially bound procolipase for the trioctanoin containing 0.07-0.42 mol mol-1 of triacetin was approximately three times higher than that for pure trioctanoin. The cooperative processes involved in complex formation did not contribute to the affinity of the interfacial lipase/(pro)colipase complex towards substrate molecules and its catalytic activity.
Tetrahedron | 1997
Omar Parve; Imre Vallikivi; Andrus Metsala; Ülo Lille; Vello Tõugu; Peeter Sikk; Tuuli Kaambre; Heiki Vija; Tõnis Pehk
Abstract The initial velocities of the enantioselective hydrolysis of the esters derived from mono- and bicyclic alcohols and hemiacetals catalysed by Lipolase™ in water have been determined. The differences in hydrolysis rates within groups of sterically similar substrates have been interpreted in terms of frontier orbital localisation.
Bioorganic & Medicinal Chemistry Letters | 1993
Omar Parve; Anne Pals; Vello Kadarpik; Lilja Lahe; Ülo Lille; Peeter Sikk; Aivar Löokene; Välimäe Toomas
Abstract Double enantioselection occurs in the case of hydrolysis of (1S,2R,5S,6R)-2-bromo-3-butanoyloxy-6-hexanoyloxybicyclo[3.2.0]heptane (13), allowing us to obtain the corresponding bromodiol (−)-(14) and epoxyalcohol (−)-(15) of high optical purity.
Bioorganic & Medicinal Chemistry Letters | 1993
Omar Parve; Anne Pals; Vello Kadarpik; Ülo Lille; Peeter Sikk; Aivar Löokene; Toomas Välimäe
Abstract The responsibility of high-purity porcine pancreatic lipase (PPL), an asymmetric catalyst, has been established quantitatively in the case of hydrolysis of the title compounds. A drastic differentiation between stereoisomeric as well as homologous substrates was observed.
Biochimica et Biophysica Acta | 1997
Laurence Kay; Zhenlin Li; Mathias Mericskay; Jose Olivares; Leone Tranqui; Eric Fontaine; Toomas Tiivel; Peeter Sikk; Tuuli Kaambre; Jeane-Lyze Samuel; L. Rappaport; Yves Usson; Xavier Leverve; Denise Paulin; Valdur Saks
Journal of Molecular and Cellular Cardiology | 2000
Pierre Dos Santos; Mayis K. Aliev; Philippe Diolez; François Duclos; P. Besse; Simone Bonoron-Adèle; Peeter Sikk; Paul Canioni; Valdur Saks
Collection of Czechoslovak Chemical Communications | 1981
Ants Lääne; Vladimír Chytrý; Mati Haga; Peeter Sikk; Aavo Aaviksaar; Jindřich Kopeček
Die Makromolekulare Chemie, Rapid Communications | 1982
Vladimír Chytrý; Jindřich Kopeček; Peeter Sikk; Riivo Sinijärv; Aavo Aaviksaar
Biophysical Journal | 2011
Minna Karu-Varikmaa; Merle Saaremäe; Peeter Sikk; Tuuli Kaambre; Madis Metsis; Valdur Saks