Meeting Abstract

P2.140  Monday, Jan. 5  Does diffusion matter? Assessing the importance of diffusion in phosphagen metabolism for a fast start WERNER, Bianca J*; ROOT, Robert G; Lafayette College; Lafayette College wernerb@lafayette.edu

The Phospho-Creatine Shuttle is a buffering system that stores and transports energy for muscle contractions, among other metabolic processes. Phosphocreatine (denoted PCr), is a phosphagen that serves a dual purpose in cells: 1) it acts as an energy reserve, providing large amounts of energy within short time periods by maintaining a high ATP/ADP concentration ratio in the A band of myofibrils; and 2) it transports energy to myofibrils from mitochondria located adjacent to I bands of the myofibrils. PCr is synthesized in mitochondria, then diffuses into myofibrils. Is this PCr diffusion fast enough to contribute significantly to maintenance of high ATP concentration in fully contracting muscles, considering fast starts occur in 10-100 milliseconds? Constructing a mathematical model using parameters derived from published results of other’s experiments, we find that diffusing PCr does materially assist in buffering ATP.