AJP - Cell Physiology, Vol 236, Issue 3 111-C116, Copyright © 1979 by American Physiological Society
Effects of serum on membrane transport. III. Serum and inhibition of lysine transport
P. R. Strauss
Rabbit lung macrophages have been shown to transport lysine by means of a
single carrier-mediated system that is depressed after relatively short
incubations with 1% normal rabbit serum (NRS). Our present results show
that three amino acids, glutamine, phenylalanine and tyrosine, at or near
the concentration found in 1% NRS, are involved intracellularly in
regulating lysine influx across the plasma membrane. The means by which
they do so requires a 20- to 30-min preincubation, the effect is maintained
for 45 min in their absence, and both maximal velocity and affinity of
lysine for its carrier are altered in an apparently uncompetitive fashion.
The kinetic data are unlike those reported for other trans phenomena
involved in amino acid transport. We propose that the effect of internal
inhibitor on lysine influx probably does not involve the direct interaction
of the transamino acid on the lysine carrier.
