Which protein is an enzyme that helps transfer phosphate groups in muscle metabolism?

Which protein is an enzyme that helps transfer phosphate groups in muscle metabolism?

• A. Creatine kinase.
• B. Myoglobin
• C. Troponin
• D. Ischemia.

Answer: (A)

Creatine kinase is the enzyme that transfers high-energy phosphate groups in muscle metabolism. It catalyzes the transfer of a phosphate from phosphocreatine to ADP to rapidly regenerate ATP during brief, intense activity. This phosphocreatine system acts as a quick energy buffer, keeping ATP levels up when rapid contraction is needed and oxidative ATP production can’t respond immediately. In muscle, CK exists in different forms that shuttle phosphate between mitochondria and the cytosol to sustain energy supply for contraction. The other options don’t perform this phosphate-transfer role: myoglobin stores and delivers oxygen in muscle; troponin is a calcium-sensitive regulator of contraction; and ischemia is a condition of reduced blood flow, not a protein.

Creatine kinase is the enzyme that transfers high-energy phosphate groups in muscle metabolism. It catalyzes the transfer of a phosphate from phosphocreatine to ADP to rapidly regenerate ATP during brief, intense activity. This phosphocreatine system acts as a quick energy buffer, keeping ATP levels up when rapid contraction is needed and oxidative ATP production can’t respond immediately. In muscle, CK exists in different forms that shuttle phosphate between mitochondria and the cytosol to sustain energy supply for contraction. The other options don’t perform this phosphate-transfer role: myoglobin stores and delivers oxygen in muscle; troponin is a calcium-sensitive regulator of contraction; and ischemia is a condition of reduced blood flow, not a protein.