System y+L-like activities account for high and low @entity535 transport phenotypes in XXXX erythrocytes.

@entity1 @entity4307 @entity52312 @entity535 @entity9640 @entity1372 @entity8816 @entity1853 @entity1573 @entity9108 @entity376 @entity972 @entity1168
The functional properties of the transport of @entity376 across the @entity1573 erythrocyte membrane were investigated. The animal population studied (male Leghorn @entity1573 , 6-14 weeks old) was found to consist of two groups presenting either low (LT, 19 individuals) or @entity1168 ( @entity1168 , 20 individuals). The rates of influx in the two groups, measured at a concentration of @entity9108 of 1 microm, differed by a factor of 34. The transport activities observed in LT and @entity1168 erythrocytes were compatible with the general features of system y+L, but showed some differences in specificity. The transporter in the LT group was found to bind @entity9108 , @entity4307 , @entity1853 and @entity9640 with high affinity, in the presence of @entity1372 , as described for system y+L in @entity1 erythrocytes. The activity present in @entity1168 erythrocytes exhibited a much lower affinity for @entity4307 , but was able to interact strongly with @entity9640 and @entity1853 . The specificity pattern of the @entity1168 transporter, has not been described in other cell types. In other respects, the properties of the two systems were similar. @entity1372 replacement with @entity972 , drastically reduced the affinity for @entity4307 , without affecting @entity376 transport. Both transporters function as tightly coupled exchangers, are inactivated by @entity52312 and resistant to @entity8816 . These findings explain previous results obtained in selective breeding experiments of @entity1573 with high and low @entity535 transport activity.
