Intestinal Dipeptide Transport in Normal a N D Cystinuric Subjects
نویسندگان
چکیده
1. The absorption of lysine and two lysine-containing dipeptides was studied in normal and cystinuric subjects by jejunal perfusion. Absorption of each dipeptide was compared with that of its constituent amino acids. 2. In normal subjects lysine was better absorbed from the dipeptide glycyl-L-lysine than from the equivalent amino acid mixture. In cystinuric patients lysine was absorbed very poorly in its free form but was absorbed normally from the dipeptide. In cystinuric patients lysine ‘was also absorbed faster as L-lysyl-L-lysine than as free lysine. 3. During perfusion of both dipeptides significantly greater quantities of free lysine were found within the intestinal lumen in cystinuric subjects than in normal subjects. This is thought to be due to back-diffusion after hydrolysis of dipeptide by the mucosa. 4. These observations confirm the existence of dipeptide transport systems independent of those for free amino acids.
منابع مشابه
Dipeptide absorption in man.
A quantitative perfusion method has been used to study intestinal absorption of two dipeptides-glycyl-glycine and glycyl-l-alanine-in normal subjects. In each case, the constituent amino acids were absorbed faster when presented as dipeptides than as free amino acids, suggesting intact dipeptide transport. During absorption constituent amino acids were measured within the lumen and it is sugges...
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