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THE INFLUX OF ISOLEUCINE INTO THE CEREBRAL HEMISPHERES AND CEREBELLUM: CARRIER‐MEDIATED TRANSPORT AND DIFFUSION
Author(s) -
Daniel P. M.,
Pratt O. E.,
Wilson Penelope A.
Publication year - 1977
Publication title -
quarterly journal of experimental physiology and cognate medical sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.925
H-Index - 101
eISSN - 1469-445X
pISSN - 0033-5541
DOI - 10.1113/expphysiol.1977.sp002386
Subject(s) - isoleucine , kinetics , diffusion , cerebellum , chemistry , facilitated diffusion , michaelis–menten kinetics , biophysics , biochemistry , medicine , amino acid , biology , endocrinology , leucine , thermodynamics , enzyme , membrane , physics , enzyme assay , quantum mechanics
The influx of L‐isoleucine from the blood into the cerebral hemispheres, and into the cerebellum, of the living rat was studied. When various raised levels of L‐isoleucine were maintained in the circulation, influx did not increase in proportion to the raised blood levels, which showed that a carrier‐mediated transport was being saturated. It was found that the values for influx could not be explained precisely by Michaelis‐Menten kinetics. The divergence of the observed values for influx, from those which were obtained by the application of Michaelis‐Menten kinetics, could be explained if part of the influx was due to a small, non‐saturable component. This minor component of influx may be due to diffusion or to a second carrier‐mediated transport system that is not readily saturated.