-transparent.png){kind=logo}
Transport of adenine and hypoxanthine in human erythrocytes proceeds via two mechanisms: (1) a common carrier for both nucleobases and (2) unsaturable permeation 4-5-fold faster for adenine for hypoxanthine. The latter process was resistant to inactivation by diazotized sulfanilic acid. Carrier mediated transport of both substrates was investigated using zero-trans and equilibrium exchange protocols. Adenine displayed a much higher affinity for the carrier (Km approximately 5-8 microM) than hypoxanthine (Km approximately 90-120 microM) but maximum fluxes at 25 degrees C were generally 5-10-fold lower for adenine (Vmax approximately 0.6-1.4 pmol/microliters per s) than for hypoxanthine (Vmax approximately 9-11 pmol/microliters per s). The carrier behaved symmetrically with respect to influx and efflux for both substrates. Adenine, but not hypoxanthine reduced carrier mobility more than 10-fold. The mobility of the unloaded carrier, calculated from the kinetic data of either hypoxanthine or adenine transport, was the same thus providing further evidence that these substrates share a common transporter and that their membrane transport is adequately described by the alternating conformation model of carrier-mediated transport.
M Kraupp, and
R Marz, and
G Prager, and
W Kommer, and
M Razavi, and
M Baghestanian, and
P Chiba
January 1979,
Advances in experimental medicine and biology,
M Kraupp, and
R Marz, and
G Prager, and
W Kommer, and
M Razavi, and
M Baghestanian, and
P Chiba
February 1967,
Biochimica et biophysica acta,
M Kraupp, and
R Marz, and
G Prager, and
W Kommer, and
M Razavi, and
M Baghestanian, and
P Chiba
April 1983,
Biochimica et biophysica acta,
M Kraupp, and
R Marz, and
G Prager, and
W Kommer, and
M Razavi, and
M Baghestanian, and
P Chiba
October 1982,
The Journal of biological chemistry,
M Kraupp, and
R Marz, and
G Prager, and
W Kommer, and
M Razavi, and
M Baghestanian, and
P Chiba
July 1975,
Hoppe-Seyler's Zeitschrift fur physiologische Chemie,
M Kraupp, and
R Marz, and
G Prager, and
W Kommer, and
M Razavi, and
M Baghestanian, and
P Chiba
February 1962,
Biochimica et biophysica acta,
M Kraupp, and
R Marz, and
G Prager, and
W Kommer, and
M Razavi, and
M Baghestanian, and
P Chiba
January 1981,
The International journal of biochemistry,
M Kraupp, and
R Marz, and
G Prager, and
W Kommer, and
M Razavi, and
M Baghestanian, and
P Chiba
December 1987,
Clinica chimica acta; international journal of clinical chemistry,
M Kraupp, and
R Marz, and
G Prager, and
W Kommer, and
M Razavi, and
M Baghestanian, and
P Chiba
February 1985,
Biochimica et biophysica acta,
M Kraupp, and
R Marz, and
G Prager, and
W Kommer, and
M Razavi, and
M Baghestanian, and
P Chiba
November 1977,
The Biochemical journal,
