AJP - Regu Fuel your research with LabChart
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

Am J Physiol Regul Integr Comp Physiol 260: R563-R569, 1991;
0363-6119/91 $5.00
This Article
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Reshkin, S. J.
Right arrow Articles by Ahearn, G. A.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Reshkin, S. J.
Right arrow Articles by Ahearn, G. A.

AJP - Regulatory, Integrative and Comparative Physiology, Vol 260, Issue 3 563-R569, Copyright © 1991 by American Physiological Society

ARTICLES

Intestinal glycyl-L-phenylalanine and L-phenylalanine transport in a euryhaline teleost

S. J. Reshkin and G. A. Ahearn
Department of Zoology, University of Hawaii, Manoa, Honolulu 96822.

The transport mechanisms for the dipeptide glycyl-L-phenylalanine (Gly-Phe) and L-phenylalanine (Phe) were characterized in fish intestinal brush-border membrane vesicles (BBMV). Gly-Phe was rapidly hydrolyzed only intravesicularly with almost total hydrolysis occurring even at 10 s. Dipeptide uptake was not stimulated by an inward gradient of Na, K, or H. Phe uptake was stimulated by an inward gradient of either Na or K but displayed an overshoot phenomenon only in the presence of an Na gradient. Kinetic analysis of the effect of substrate concentration on transport rate revealed that transport of both Gly-Phe and Phe occurred by a saturable process conforming to Michaelis-Menten kinetics. The Km for Gly-Phe was 9.8 +/- 3.5 mM, whereas that for Phe in the presence of Na or K, respectively, was 0.74 +/- 0.13 and 1.1 +/- 0.37 mM. Maximum uptake for Gly-Phe and for Phe in the presence of Na and K was 5.1, 0.9, and 0.4 nmol.mg and protein-1.5 s-1, respectively. Gly-Phe and Phe transport displayed different patterns of inhibition by dipeptides and amino acids. These results suggest that Gly-Phe and Phe are transported via different mechanisms, with Gly-Phe being hydrolyzed during a carrier-mediated, cation-independent process and Phe being transferred via a Na+ cotransport process similar to that described in mammals. During conditions of high luminal dipeptide concentrations, the Gly-Phe pathway may make a significant contribution to total Phe uptake.


This article has been cited by other articles:


Home page
 Am. J. Physiol. Regul. Integr. Comp. Physiol.Home page
L. Ingrosso, S. Marsigliante, V. Zonno, C. Storelli, and S. Vilella
An L-proline-dependent proton flux is located at the apical membrane level of the eel enterocytes
Am J Physiol Regulatory Integrative Comp Physiol, November 1, 2000; 279(5): R1619 - R1624.
[Abstract] [Full Text] [PDF]


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Visit Other APS Journals Online