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'Sarcoplasm ic Reticulum' in keywords
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1983 (1)
1982 (1)
1Author    G. Inesi, M. Kurzmack, D. Kosk-Kosicka, D. Lewis, H. Scofano, H. G. Uim Araes-MottaRequires cookie*
 Title    Equilibrium and Kinetic Studies of Calcium Transport and ATPase Activity in Sarcoplasmic Reticulum  
 Abstract    A number o f equilibrium and kinetic m easurem ents are presented to characterize the partial reactions o f the ATPase and transport cycle in sarcoplasm ic reticulum vesicles. The cycle begins with calcium and nucleotide binding on sites available on the outer surface o f the vesicles. A phosphorylated enzyme intermediate is then formed, and the calcium sites are subjected to a change in their orientation and their affinity for calcium . It is shown that steps involved in cal­ cium release on the inner side o f the vesicles are rate lim iting for the cycle, and are follow ed by hydrolytic cleavage o f the intermediate with release o f inorganic phosphate and recycling o f the enzyme. 
  Reference    Z. Naturforsch. 37c, 685 (1982); received February 6 /M arch 23 1982 
  Published    1982 
  Keywords    Calcium, Transport, ATPase, Sarcoplasm ic Reticulum 
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 TEI-XML for    default:Reihe_C/37/ZNC-1982-37c-0685.pdf 
 Identifier    ZNC-1982-37c-0685 
 Volume    37 
2Author    Hector Barrabin, Leopoldo De MeisRequires cookie*
 Title    Phosphorylation of Ca-ATPase of Sarcoplasmic Reticulum with Different Substrates  
 Abstract    ATP and G TP as substrate for phosphorylation o f sarcoplasm ic reticulum A TPase are compared. Maximal levels o f phosphoenzyme are between 4.5 and 4.8 nmol per mg o f protein when either substrate is used provided that phosphoenzym e hydrolysis are strongly inhibited by high calcium concentration (20 mM) and low tem peratures (0 ° C) . T he m axim al values obtained with G TP are lower than those previously reported. It is shown that this difference is due to underestim ation o f the specific activity o f labeled nucleotides used in previous studies, as revealed by U V absorption and H PLC analysis. The dependence o f the phosphoenzyme levels on calcium concentration, pH and tem perature confirm previous findings indicating that ATP, but no G T P , accelerates the rate limiting step o f the catalytic cycle. 
  Reference    Z. Naturforsch. 38c, 845 (1983); received M arch 2 4/Ju n e 16 1983 
  Published    1983 
  Keywords    Calcium, ATPase, Sarcoplasm ic Reticulum, H PLC, N ucleotides 
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 TEI-XML for    default:Reihe_C/38/ZNC-1983-38c-0845.pdf 
 Identifier    ZNC-1983-38c-0845 
 Volume    38