Transport of the aromatic amino acids into isolated rat liver cells. Properties of uptake by two distinct systems.
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| Abstract |
The transport of the aromatic amino acids into isolated rat liver cells was studied. There was a rapid and substantial binding of the aromatic amino acids, L-alanine and L-leucine to the plasma membrane. This has important consequences for the determination of rates of transport and intracellular concentrations of the amino acids. Inhibition studies with a variety of substrates of various transport systems gave results consistent with aromatic amino acid transport being catalysed by two systems: a 2-aminobicyclo(2,2,1)heptane-2-carboxylic acid (BCH)-insensitive aromatic D- and L-amino acid-specific system, and the L-type system (BCH-sensitive). The BCH-insensitive component of transport was Na+-independent and facilitated non-concentrative transport of the aromatic amino acids; it was unaffected by culture of liver cells for 24 h, by 48 h starvation, dexamethasone phosphate or glucagon. Kinetic properties of the BCH-inhibitable component were similar to those previously reported for the L2-system in liver cells. The BCH-insensitive component was a comparatively low-Km low-Vmax. transport system that we suggest is similar to the T-transport system previously seen only in human red blood cells. The results are discussed with reference to the importance of the T- and L-systems in the control of aromatic L-amino acid degradation in the liver.
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| Authors | M Salter, R G Knowles, C I Pogson |
| Journal | The Biochemical journal (Biochem J) Vol. 233 Issue 2 Pg. 499-506 (Jan 15 1986) ISSN: 0264-6021 [Print] England |
| PMID | 3954748 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't) |
| Chemical References |
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