Only answer \'B\' please. The more detali the better. Thank you! When SERCA is i
ID: 166495 • Letter: O
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Only answer 'B' please. The more detali the better. Thank you!
When SERCA is incubated with [gamma-^32P]-ATP and calcium at 0 degree C for 20 seconds and analyzed by gel electrophoresis, a radioactive band is observed at the molecular weight corresponding to full-length SERCA. Why is a labeled band observed and would you expect a similar band if you were performing a similar assay, with a suitable substrate, for any ATPase transporter? To study the mechanism of SERCA, you prepare membrane vesicles containing this protein oriented such that its ATP binding site is on the outer surface of the vesicle. To measure pump activity, you use an assay that detects the formation of inorganic phosphate in the medium. When you add calcium and ATP to the medium, you observe phosphate production for only a short period of time. Only after the addition of calcimycin, a molecule that makes membranes selectively permeable to calcium, do you observe sustained phosphate production. Explain.Explanation / Answer
SERCA is present within sarcoplasmic reticulum. Calcimycin is an antibiotic and ion carrier which is mobile and transports calcium and other cations across membranes. It uncouples oxidative phosphorylation.
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