Na+-independent and nonstereospecific transport of 2-hydroxy 4-methylthiobutanoic acid by brush border membrane vesicles from chick small intestine.
1. The transport of L- and DL-2-hydroxy 4-methylthiobutanoic acid (HMB), the methionine hydroxy analogue, by brush border membrane vesicles (BBMV) from chick small intestine was the sum of a saturable Michaelian component and a diffusive term. 2. Unlike that of L- and DL-MET, uptake was Na+-independent and electroneutral. 3. The inhibition of L-HMB transport by L-lactate, a structural analogue, and D-HMB as well, was of the competitive type. 4. Preloading of BBMV with D-HMB but not with L-lactate or L-MET trans-stimulated the influx of labelled L-HMB. 5. HMB uptake by rat and chick intestinal BBMV exhibited similar characteristics but the chick nonstereospecific transport system appeared to be unable to carry out L-lactate translocation.
Brachet
P
P
Centre de Biochimie et de Biologie Moléculaire du CNRS, Marseille, France.
Puigserver
A
A
D000818:Animals; D001667:Binding, Competitive; D001692:Biological Transport; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D002645:Chickens; D007421:Intestine, Small / Q000378:metabolism*; D007700:Kinetics; D007773:Lactates / Q000494:pharmacology; D008564:Membrane Potentials; D008715:Methionine / Q000031:analogs & derivatives* / Q000378:metabolism; D008871:Microvilli / Q000378:metabolism; D051381:Rats; D012964:Sodium / Q000494:pharmacology*
D007773:Lactates; C008391:alpha-hydroxy-gamma-methylmercaptobutyric acid; D012964:Sodium; D008715:Methionine