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Updated: Oct 18, 2025

Models and Methods to Evaluate Transport of Drug Delivery Systems Across Cellular Barriers
Published on: October 17, 2013
Characteristic attributes limiting the transport rates in NCX orthologs
Bosmat Refaeli1, Reuben Hiller1, Daniel Khananshvili1
1Department of Physiology and Pharmacology, Sackler School of Medicine, Tel Aviv University, Ramat Aviv 69978, Israel.
Abstract:
The Na+/Ca2+ exchangers (NCXs) modulate the Ca2+ signaling and homeostasis in health and disease. The transport cycle turnover rates (kcat) and the kcat/Km values of eukaryotic NCXs are ~104-times higher than those of prokaryotic NCXs. Three ion-coordinating residues (out of twelve) differ between eukaryotic NCXs and NCX_Mj. The replacement of three ion-coordinating residues in NCX_Mj does not increase kcat, probably due to the structural rigidity of NCX_Mj. Phospholipids and cholesterol increase (up to 10-fold) the transport rates in the cardiac NCX1.1, but not in NCX_Mj. A lipid environment can partially contribute to the huge kinetic variances among NCXs.
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