@entity17463 reacts with the @entity413 carrier of @entity1 erythrocytes at a rate which is greatly altered in the presence of competitive inhibitors of @entity413 transport. Inhibitors bound to the carrier on the outer surface of the membrane, either at the substrate site ( @entity7969 ) or at the external inhibition site ( @entity16802 and @entity21146 ), more than double the reaction rate. Inhibitors bound at the internal inhibition site (cytochalasin B and @entity2671 ), protect the system against @entity17464 . After treatment with @entity17464 , the maximum transport rate falls to less than one-third, and the properties of the binding sites are modified in unexpected ways. The affinity of externally bound inhibitors rises: @entity16802 is bound up to seven times more strongly and @entity21146 and maltose twice as strongly. The affinity of cytochalasin B, bound at the internal inhibition site, falls to half while that of @entity2671 is little changed. The affinity of external @entity413 falls slightly. @entity2671 prevents both the fall in transport activity and the increase in @entity16802 affinity produced by @entity17464 . An inhibitor of anion transport has no effect on the reaction. The observations support the following conclusions: @entity17464 produces its effects on the @entity413 transport system by reacting with the carrier on the outer surface of the membrane. The carrier assumes distinct inward-facing and outward-facing conformations, and @entity17464 reacts with only the outward-facing form. The @entity1432 group with which @entity17464 is presumed to react is not present in either the substrate site or the internal or external inhibitor site.(ABSTRACT TRUNCATED AT 250 WORDS)

Reaction of the XXXX carrier of erythrocytes with @entity17463 : evidence for inward-facing and outward-facing carrier conformations.

@entity1 :: ('9606', 'Species') :: ['human'] @entity7969 :: ('MESH:D008320', 'Chemical') :: ['maltose'] @entity17464 :: ('CHEBI:16094', 'Chemical') :: ['tetrathionate', 'Tetrathionate'] @entity16802 :: ('MESH:D010693', 'Chemical') :: ['phloretin'] @entity1432 :: ('CHEBI:29256', 'Chemical') :: ['thiol'] @entity17463 :: ('MESH:D013776', 'Chemical') :: ['Sodium tetrathionate'] @entity2671 :: ('MESH:D000735', 'Chemical') :: ['androstenedione', 'Androstenedione'] @entity413 :: ('MESH:D005947', 'Chemical') :: ['glucose'] @entity21146 :: ('MESH:D010695', 'Chemical') :: ['phlorizin']
@entity413 :: (MESH:D005947,Chemical) :: ['glucose']
