Abstract
Sarcoplasmic reticulum isolated from skeletal muscle of the rabbit and the Pacific dogfish (Squalus acanthias) was characterized in terms of its Ca2+-uptake at different temperatures. SR from both species showed comparable Ca2+-uptake rates at their basal body temperatures (5°C and 37°C, respectively). Only very low percentages of phosphorylase, phosphorylase kinase and phosphatase were found to be associated with the purified vesicles, once these were freed of contaminating glycogen particles. Ca2+-fluxes during contraction/relaxation-cycles in muscles were studied in a reconstituted system by measuring the inhibition of the rate of Ca2+-uptake by the sarcoplasmic reticulum and of the Ca2+-dependent activity of phosphorylase kinase, respectively, by metal-free troponin, troponin-C, parvalbumin and phosphorylase kinase; EGTA was used as an internal standard. Ca2+-binding capacities of the various proteins were determined separately by gel filtration experiments. Data obtained agreed with published values for troponin, troponin-C and parvalbumin; for phosphorylase kinase, a value of n- = 8 was found regardless of the state of phosphorylation of the enzyme. Results obtained from both types of experiments established apparent Ca2+-affinities in the following decreasing order : phosphorylase kinase ∼ parvalbumin > EGTA > troponintroponin-C, with no difference found between the non-phosphorylated and phosphorylated forms of phosphorylase kinase. Apparent equilibrium constants for these Ca2+-complexes, relative to EGTA, were in agreement with published values obtained from classical equilibrium studies. Similar results were obtained with proteins isolated from rabbit and dogfish muscle. No indication of protein-protein interactions affecting Ca2+-fluxes could be found in such a reconstituted system, except for the singular case of a slight increased inhibition of phosphorylase kinase by parvalbumin following phosphorylation of the enzyme.
| Original language | English |
|---|---|
| Pages (from-to) | 615-624 |
| Number of pages | 10 |
| Journal | Biochimie |
| Volume | 61 |
| Issue number | 5-6 |
| DOIs | |
| State | Published - Sep 10 1979 |
| Externally published | Yes |
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ASJC Scopus subject areas
- Biochemistry
Cite this
Exchange of calcium between muscle Ca2+-binding proteins. / Moeschler, Hans J.; Malencik, Dean A.; Pocinwong, Sitivad; Alaba, Olusola; Kerrick, W. Glenn; Fischer, Edmond H.
In: Biochimie, Vol. 61, No. 5-6, 10.09.1979, p. 615-624.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Exchange of calcium between muscle Ca2+-binding proteins
AU - Moeschler, Hans J.
AU - Malencik, Dean A.
AU - Pocinwong, Sitivad
AU - Alaba, Olusola
AU - Kerrick, W. Glenn
AU - Fischer, Edmond H.
PY - 1979/9/10
Y1 - 1979/9/10
N2 - Sarcoplasmic reticulum isolated from skeletal muscle of the rabbit and the Pacific dogfish (Squalus acanthias) was characterized in terms of its Ca2+-uptake at different temperatures. SR from both species showed comparable Ca2+-uptake rates at their basal body temperatures (5°C and 37°C, respectively). Only very low percentages of phosphorylase, phosphorylase kinase and phosphatase were found to be associated with the purified vesicles, once these were freed of contaminating glycogen particles. Ca2+-fluxes during contraction/relaxation-cycles in muscles were studied in a reconstituted system by measuring the inhibition of the rate of Ca2+-uptake by the sarcoplasmic reticulum and of the Ca2+-dependent activity of phosphorylase kinase, respectively, by metal-free troponin, troponin-C, parvalbumin and phosphorylase kinase; EGTA was used as an internal standard. Ca2+-binding capacities of the various proteins were determined separately by gel filtration experiments. Data obtained agreed with published values for troponin, troponin-C and parvalbumin; for phosphorylase kinase, a value of n- = 8 was found regardless of the state of phosphorylation of the enzyme. Results obtained from both types of experiments established apparent Ca2+-affinities in the following decreasing order : phosphorylase kinase ∼ parvalbumin > EGTA > troponintroponin-C, with no difference found between the non-phosphorylated and phosphorylated forms of phosphorylase kinase. Apparent equilibrium constants for these Ca2+-complexes, relative to EGTA, were in agreement with published values obtained from classical equilibrium studies. Similar results were obtained with proteins isolated from rabbit and dogfish muscle. No indication of protein-protein interactions affecting Ca2+-fluxes could be found in such a reconstituted system, except for the singular case of a slight increased inhibition of phosphorylase kinase by parvalbumin following phosphorylation of the enzyme.
AB - Sarcoplasmic reticulum isolated from skeletal muscle of the rabbit and the Pacific dogfish (Squalus acanthias) was characterized in terms of its Ca2+-uptake at different temperatures. SR from both species showed comparable Ca2+-uptake rates at their basal body temperatures (5°C and 37°C, respectively). Only very low percentages of phosphorylase, phosphorylase kinase and phosphatase were found to be associated with the purified vesicles, once these were freed of contaminating glycogen particles. Ca2+-fluxes during contraction/relaxation-cycles in muscles were studied in a reconstituted system by measuring the inhibition of the rate of Ca2+-uptake by the sarcoplasmic reticulum and of the Ca2+-dependent activity of phosphorylase kinase, respectively, by metal-free troponin, troponin-C, parvalbumin and phosphorylase kinase; EGTA was used as an internal standard. Ca2+-binding capacities of the various proteins were determined separately by gel filtration experiments. Data obtained agreed with published values for troponin, troponin-C and parvalbumin; for phosphorylase kinase, a value of n- = 8 was found regardless of the state of phosphorylation of the enzyme. Results obtained from both types of experiments established apparent Ca2+-affinities in the following decreasing order : phosphorylase kinase ∼ parvalbumin > EGTA > troponintroponin-C, with no difference found between the non-phosphorylated and phosphorylated forms of phosphorylase kinase. Apparent equilibrium constants for these Ca2+-complexes, relative to EGTA, were in agreement with published values obtained from classical equilibrium studies. Similar results were obtained with proteins isolated from rabbit and dogfish muscle. No indication of protein-protein interactions affecting Ca2+-fluxes could be found in such a reconstituted system, except for the singular case of a slight increased inhibition of phosphorylase kinase by parvalbumin following phosphorylation of the enzyme.
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UR - http://www.scopus.com/inward/citedby.url?scp=0018707459&partnerID=8YFLogxK
U2 - 10.1016/S0300-9084(79)80159-5
DO - 10.1016/S0300-9084(79)80159-5
M3 - Article
C2 - 115501
AN - SCOPUS:0018707459
VL - 61
SP - 615
EP - 624
JO - Biochimie
JF - Biochimie
SN - 0300-9084
IS - 5-6
ER -