Calcium uptake by sarcoplasmic reticulum prepared from the·Asynchronous flight muscles of Phormia terrae-novae

Abstract

Abstract 1. 1. Sarcoplasmic reticulum (SR) vesicles have been purified from the asynchronous flight muscles of the blowfly Phormia terrae-novae . 2. 2. In these SR preparations the calcium pump protein ( M r = 110,000 ) is the dominating protein (approx 65% of total protein). 3. 3. The calcium uptake rate ( 6.6 ± 0.02 μmols of Ca 2+ /mg 110,000 M r protein in 1 min) is comparable to that of locust flight muscle and cockroach leg muscle SR. 4. 4. In contrast, total calcium transport activity measured in whole muscle homogenates is much lower in the asynchronous flight muscles of the blowfly than in locust flight and cockroach leg muscles.