scholarly journals The interaction of the calcium-binding protein (troponin C) with bivalent cations and the inhibitory protein (troponin I)

1974 ◽  
Vol 137 (2) ◽  
pp. 145-154 ◽  
Author(s):  
J. F. Head ◽  
S. V. Perry
Keyword(s):  
Skeletal Muscle ◽  
Calcium Binding ◽  
Troponin I ◽  
Binding Protein ◽  
Sodium Dodecyl ◽  
Psoas Muscle ◽  
Calcium Binding Protein ◽  
Sedimentation Equilibrium ◽  
Free Form ◽  
Inhibitory Protein

1. The molecular weight of the calcium-binding protein of rabbit white skeletal muscle was estimated to be 18500 by sedimentation equilibrium and electrophoresis in sodium dodecyl sulphate. 2. Addition of 2 Ca2+ ions per molecule produced reversible changes in the u.v.-absorption spectrum that are interpreted as arising from conformational changes in the structure of the protein. 3. Cd2+ was almost as effective as Ca2+ in producing the spectral changes. Other bivalent metal ions, particularly Mg2+, were less effective. 4. Binding of Ca2+ by the calcium-binding protein produced an increase in mobility to the anode on electrophoresis in 6m-urea at pH8.6. The Ca2+-saturated form of the protein was more retarded on gel filtration than the Ca2+-free form. 5. In the presence of Ca2+ the calcium-binding protein formed an equimolar complex with the inhibitory protein. This complex was stable in 8m-urea and in the pH range 7.0–8.6. 6. An isotope-dilution method for the measurement of the content of calcium-binding protein in whole muscle is described. In rabbit psoas muscle the ratio of actin monomers to molecules of calcium-binding protein was approx. 7:1. Similar values were obtained for red skeletal and cardiac muscle. 7. Evidence is presented indicating that in the rabbit the inhibitory protein of the troponin complex of red skeletal and cardiac muscles is different from the inhibitory protein of white skeletal muscle.

The Isolation and Characterization of the ATPase Inhibitory Protein (TN-I) from Bovine Cardiac Muscle

1975 ◽  
Vol 53 (11) ◽  
pp. 1207-1213 ◽  
Author(s):  
L. D. Burtnick ◽  
W. D. McCubbin ◽  
C. M. Kay
Keyword(s):  
Molecular Weight ◽  
Cardiac Muscle ◽  
Calcium Binding ◽  
Sodium Dodecyl ◽  
Basic Amino Acid ◽  
Sedimentation Equilibrium ◽  
Amino Acid Residues ◽  
Inhibitory Protein ◽  
Isolation And Characterization

The inhibitory component of the troponin complex (TN-I) was purified from bovine cardiac muscle, using a combination of ion exchange and molecular exclusion chromatographies in the presence of urea. It has the ability to inhibit the Mg2+-activated ATPase (EC 3.6.1.3) of a synthetic cardiac actomyosin preparation and this inhibition is reversed by the addition of cardiac calcium binding component of troponin (TN-C). Conventional sedimentation equilibrium experiments suggest a molecular weight for cardiac TN-I of 22 900 ± 500. However, sodium dodecyl sulfate (SDS) gels indicate a molecular weight of 27 000 ± 1000. The mobility of TN-I on SDS gels may be anomalous due to the high proportion of basic amino acid residues in the protein. Cardiac TN-I and TN-C interact to form a tight complex, even in the presence of 6 M urea. The results of this study invite direct comparison with results published for rabbit skeletal TN-I.

scholarly journals Phosphorylation of the ‘37000 component’ of the troponin complex (troponin-T)

1973 ◽  
Vol 131 (2) ◽  
pp. 425-428 ◽  
Author(s):  
S. V. Perry ◽  
H. A. Cole
Keyword(s):  
Calcium Binding ◽  
Troponin T ◽  
Binding Protein ◽  
Calcium Binding Protein ◽  
Inhibitory Protein ◽  
Troponin Complex

Most of the phosphorus present in the troponin complex, which on average contains 1 mol of P/80000g, is associated with the ‘37000 component’ (0.6mol of P/mol). The inhibitory protein and particularly the ‘37000 component’, but not the calcium-binding protein, were phosphorylated when incubated with phosphorylase b kinase and [γ-32P]ATP.

scholarly journals Calcium-binding modulator protein from the unfertilized egg of the sea urchin Arbacia punctulata.

1979 ◽  
Vol 80 (1) ◽  
pp. 211-218 ◽  
Author(s):  
J F Head ◽  
S Mader ◽  
B Kaminer
Keyword(s):  
Sea Urchin ◽  
Calcium Binding ◽  
Troponin I ◽  
Binding Protein ◽  
Bovine Brain ◽  
Calcium Binding Protein ◽  
Free Calcium ◽  
Affinity Column ◽  
Arbacia Punctulata ◽  
Peptide Map

We have purified and partly characterized a calcium-binding protein from the unfertilized egg of the sea urchin Arbacia punctulata. This protein closely resembles the calcium-binding modulator protein of bovine brain in its molecular weight, electrophoretic mobility, amino acid analysis, and peptide map. It activates bovine brain phosphodiesterase in the presence of calcium but has no effect on the phosphodiesterase of the Arbacia egg. Densitometric scanning of acrylamide gels of arbacia egg homogenates shows the modulator protein to represent 0.1% of the total protein of the egg. At 10(-4) M free calcium, the protein binds four calcium ions per 17,000-dalton molecule. We have used a column of rabbit skeletal muscle troponin-I covalently coupled to Sepharose 4B as an affinity column to selectively purify the Arbacia egg calcium-binding protein. This column has also been used to purify bovine brain modulator protein and may prove of general use in isolating similar proteins from other sources. The technique may be particularly helpful when only small quantities of starting material are available.

scholarly journals Messenger ribonucleic acids from pig intestinal mucosa direct synthesis of calcium-binding protein in a cell-free translation system

1980 ◽  
Vol 185 (3) ◽  
pp. 601-607 ◽  
Author(s):  
H Mellersh ◽  
S Tomlinson ◽  
A Pollock
Keyword(s):  
Calcium Binding ◽  
Binding Protein ◽  
Direct Synthesis ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Duodenal Mucosa ◽  
Exchange Chromatography ◽  
Calcium Binding Protein ◽  
Translation System ◽  
Free System

mRNA from pig duodenal mucosa directs synthesis, in a wheat-germ cell-free system, of two products precipitated by antiserum to pure calcium-binding protein. One of these products has a higher molecular weight than authentic calcium-binding protein, but, like the authentic protein, is heat-stable. The other protein co-migrates with pure calcium-binding protein on sodium dodecyl sulphate/polyacrylamide-gel electrophoresis, is stable on heating to 70 degrees C for 15 min and alters its elution position on ion-exchange chromatography depending on whether Ca2+ is present in or absent from the elution buffer. The synthesized protein has these properties in common with authentic calcium-binding protein.

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