TURNOVER NUMBER OF ORGANIC CATION TRANSPORTER 2

Abstract

Organic Cation Transporter 2 (OCT2) is a transporter in the basolateral membrane of proximal tubular epithelial cells that plays a major role in active drug secretion. OCT2 accomplishes this role at a rate termed the turnover number, which is its rapidity in physically changing its configuration to transport substrates. This number informs in sicilio calculations that convert in vitro results to in vivo applications used by many pharmaceutical companies that ultimately influence clinical decisions (2,6). In my study, the turnover number was ascertained through western blots, slot blots, and kinetic transport experiments and was found to be 79.62/s. This value is substantially higher than the turnover number found in the study by Yin, et al. (3). In conjunction with the fact that pharmaceutical companies tend to estimate relative activity factors (RAF), rather than use in vitro data in their simulated calculations, and the lack of in vitro data available in the literature, my observations suggest that more studies are required to improve the accuracy of drug pharmacokinetic information.