Computer simulation of the P31 NMR equations governing the creatine kinase reaction.

A method for solving the Bloch equations that govern magnetization transfer NMR experiments is presented. It requires the numerical evaluation of a matrix exponential and lends itself to computer simulation. It is a simple, versatile method for evaluating P31-NMR magnetization transfer experiments designed to measure biochemical exchange rates. We apply the method to the saturation and inversion transfer experiments and find that the "initial slope" method of determining flux is subject to at least two interpretations. This verifies the accepted concept that biochemical models representing compartmentation and competing reaction hypotheses cannot be reliably distinguished by simply selecting values for NMR and biochemical parameters that give a "best fit" to experimental data. However, our results do indicate that a controlled manipulation of biochemical exchange rate may distinguish between these two models.