Characteristics of L-alanine transport in cardiac sarcolemmal vesicles and into isolated cardiac myocytes.

摘要: During cardiac insults, heart cells synthesise and accumulate alanine as a part of the anaerobic energy production pathway. The transport presumably influences this pathway, making it important to characterise l-alanine transporter in heart. In study, we have investigated across sarcolemma using novel approach, namely utilisation two preparations: sarcolemmal vesicles myocytes. Both preparations were isolated from same mammalian species. l-Alanine uptake both was sodium dependent. vesicles, dependent component was electrogenic saturated with an estimated Michaelis-Menten constant (K m) maximal reaction velocity (V max) 0.48±0.18 mM 279.97±64.17 pmol/mg per min respectively at room temperature. myocytes, linear sodium-containing media, K m V max 9.65±0.76 169.81±13.22 pmol/µl 10°C for sodium-dependent component. Inhibition cotransport by variety substrates indicated that is mediated A- or ASC-like system. These characteristics suggest under ischaemic conditions, efflux will be activated, thus allowing continuous other amino acids production.