Caprine cardiac sarcoplasmic reticulum isolation and biochemical characterisation with emphasis on Ca2+-adenosine triphosphatase

Abstract

This study was aimed at isolating, in its pure form, and characterizing the sarcoplasmic reticulum from caprine (Capra hircus) heart. The sarcoplasmic reticulum from thirty caprine heart ventricular homogenates was isolated and purified. It was characterized on the basis of both, its protein and lipid composition. The protein content was 142±10 mg/g of tissue. Ca 2+-ATPase activity equaled 3.75 ± 1.06mmol Pi/mg protein/min while the uptake rate was 24 ± 1.14 nmol/mg protein/min. 205kD, 110kD, 90kD, 84kD, 66kD, 55kD and 29kD molecular weight proteins were seen on an SDS polyacrylamide gel. Triglyceride, Cholesterol and Phospholipids (phosphatidylethanolamine, phosphatidylinositol, phosphatidylcholine, sphingomyelin and phosphatidylserine) were present in increasing order of their concentration. Long chain fatty acids predominated over the unsaturated ones. The ryanodine receptor displayed two binding sites for ryanodine. Characterisation encompassing the above biochemical aspects of normal caprine cardiac sarcoplasmic reticulum was thus achieved after isolating it in the pure form.