Premium
Hypophosphite transport in human erythrocytes studied by overdetermined one‐dimensional NMR exchange analysis
Author(s) -
Price William S.,
Kuchel Philip W.
Publication year - 1990
Publication title -
nmr in biomedicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.278
H-Index - 114
eISSN - 1099-1492
pISSN - 0952-3480
DOI - 10.1002/nbm.1940030203
Subject(s) - hypophosphite , overdetermined system , chemistry , organic chemistry , mathematics
The membrane transport kinetics of the disubstituted phosphorus oxyacid, hypophosphite, were studied in human red cells under equilibrium exchange conditions. Hypophosphite is an analogue of both the bicarbonate and phosphate ions and is known to be rapidly transported across the human red cell membrane via the anion transport protein, Band 3. The hypophosphite ion is a particularly useful probe of Band 3‐mediated membrane transport as the intracellular and extracellular species occur as distinct resonances in the 31 P NMR spectrum; as a result the membrane potential may also be readily inferred. We applied ‘overdetermined’ one‐dimensional exchange analysis to estimate the rates of exchange for influx and efflux. The apparent equilibrium exchange (ee) values K m eefor the hypophosphite efflux and influx were different and while the efflux parameters were not able to be unambiguously defined, the measured apparent influx kinetic transport parameters were V max ee= 1600 ± 190 amol cell −1 s −1 , and K ee m= 75±16 m M .