ISSN:
1573-904X
Keywords:
dipeptide analogues
;
peptide carrier-mediated transport
;
α-amino group
;
phenylpropionylproline
;
phenylacetylproline
;
N-benzoylproline
;
phenylacetyl-α-methyldopa
;
hippuric acid (N-benzoylglycine)
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Abstract The requirement for a free α-amino group for the intestinal peptide carrier-mediated transport was investigated. A series of dipeptide analogues without the N-terminal α-amino group [including phenyl-propionylproline, phenylacetylproline, N-benzoylproline, phenylacetyl-α-methyldopa, and hippuric acid (N-benzoylglycine)] were studied in the perfused rat intestinal segment. The absorption of phenylpropionylproline, phenylacetyl-α-methyldopa, and N-benzoylproline was concentration dependent. The transport parameters (mean ± SD) of phenylpropionylproline and N-benzoylproline were as follows: Jmax*, 0.037 (±0.019) mM; K m, 0.045 (±0.027) mM; P c*, 0.830 (±0.130); and P m*, 0.673 ± 0.049; and J max*, 1.34 (±0.24) mM; K m, 1.31 (±0.30) mM; P c*, 1.02 (±0.11); and P m* 0; respectively. The intestinal permeabilities of phenylpropionylproline, phenylacetylproline, N-benzoylproline, and hippuric acid (N-benzoylglycine) were significantly reduced by dipeptides and ceph-radine. These results strongly suggest that these dipeptide analogues, without an α-amino group, are transported by the peptide carrier and provide more direct evidence that a free α-amino group is not absolutely essential for the mucosal-cell peptide carrier-mediated transport.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1015848522228
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