Urinary Hydroxyproline Peptides*

Meilman, Edward; Urivetzky, Morton; Rapoport, Claire M.

doi:10.1172/jci104694

Cited by 110 publications

(31 citation statements)

References 22 publications

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“…Furthermore, the uptake of triglycine by the brush border membrane of the jejunal mucosa is mediated partially or totally by the dipeptide carrier system previously characterized (6). Intact absorption does not appear to be unique to triglycine since unhydrolyzed glycylprolylhydroxyproline has been recovered in the urine of human subj ects after ingestion of meals containing gelatin (19).…”

Section: Resultsmentioning

confidence: 99%

Evidence for two different modes of tripeptide disappearance in human intestine. Uptake by peptide carrier systems and hydrolysis by peptide hydrolases.

Adibi¹,

Morse²,

Masilamani³

et al. 1975

J. Clin. Invest.

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A B S T R A C T The intestinal fate of two tripeptides (triglycine and trileucine). which differ markedly in solubility and molecular weight, have been investigated by jejunal perfusion in healthy human volunteers. Rates of glycine or leucine uptake from test solutions containing triglycine or trileucine were greater than from test solutions containing corresponding amounts of free glycine or free leucine, respectively. The rate of glycine uptake from a 100 mM triglycine solution was greater than that from a 150 mM diglycine solution. At each infused load of triglycine (e.g., 1,000 imol/min) the rates (micromoles/minute per 30 cm) of either triglycine disappearance (810±40) or glycine absorption (2,208±+122) were markedly greater than the luminal accumulation rates of either diglycine (56±10) or free glycine (110±18). The luminal accumulation rate of free leucine during infusion of a 5 mM trileucine solution was over threefold greater than that of free glycine during the infusion of a 5 mM triglycine solution. Luminal fluid exhibited no hydrolytic activity against triglycine, but contained some activity against trileucine. Saturation of free amino acid carrier system with a large load of leucine did not affect glycine absorption rate from a triglycine test solution, but isoleucine markedly inhibited the uptake of leucine from a trileucine solution. When the carrier system for dipeptides was saturated with a large amount of glycyl-A preliminary account of this work has been previously published (1974. Gastroenterology. 66: 657) leucine, the disappearance rate of triglycine was considerably reduced while that of trileucine remained unaffected. After addition of glycylleucine to tripeptide solutions, there was a minimal increase in the luminal accumulation of diglycine, while dileucine accumulation was increased by 62-fold.These studies suggest that the modes of intestinal disappearance of the above two tripeptides are different. Triglycine is taken up intact by human jejunum; this uptake is mediated totally or partially by the carrier system which also transports dipeptides. In contrast, trileucine is hydrolyzed to leucine and dileucine mostly on the cell surface and a small fraction is hydrolyzed in the gut lumen; these hydrolytic products are then taken up by the free amino acid and dipeptide carrier systems, respectively.

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Section: Resultsmentioning

confidence: 99%

Evidence for two different modes of tripeptide disappearance in human intestine. Uptake by peptide carrier systems and hydrolysis by peptide hydrolases.

Adibi¹,

Morse²,

Masilamani³

et al. 1975

J. Clin. Invest.

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“…The dietary intake of gelatin has resulted in a marked increase of urinary excretion of bound hydroxyproline (3,4). The amino acid composition of urinary hydroxyproline peptides before (5,6) and after (6) gelatin feeding in normal subjects suggests that urinary hydroxyproline peptides are endproducts of collagen degradation. The predominant urinary hydroxyproline peptides, prolyl-hydroxyproline and glycyl-prolyl-hydroxyproline, contain amino acid sequences known to occur frequently in the collagen molecule (7).…”

Section: Introductionmentioning

confidence: 99%

The quantitative relationship of urinary peptide hydroxyproline excretion to collagen degradation

Weiss¹,

Klein²

1969

J. Clin. Invest.

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A B S T R A C r To determine the quantitative relationship of urinary hydroxyproline peptide excretion to collagen breakdown, known quantities of radioactive hydroxyproline peptides were administered to unlabeled animals and excertion of radioactivity in respiratory carbon dioxide, urine, and feces was measured. The major routes of excretion of collagen peptide metabolites were respiratory carbon dioxide (75%) and urine, as hydroxyproline-containing peptides (25%).Since the predominant urine hydroxyproline peptide linkage is prolyl-hydroxyproline, L-prOlyl-L-hydroxyproline-3H was administered to unlabeled animals. Greater than 80% of the administered dipeptide was excreted in urine, suggesting that this peptide linkage is not hydrolyzed to a significant extent in vivo.These data suggest that urinary hydroxyproline excretion is a "fairly" sensitive indicator of collagen breakdown and can be used at the clinical level to quantitate changes in collagen breakdown. creted in urine, about 97% in the form of peptides and 3% as the free imino acid (3). The dietary intake of gelatin has resulted in a marked increase of urinary excretion of bound hydroxyproline (3,4). The amino acid composition of urinary hydroxyproline peptides before (5, 6) and after (6) gelatin feeding in normal subjects suggests that urinary hydroxyproline peptides are endproducts of collagen degradation. The predominant urinary hydroxyproline peptides, prolyl-hydroxyproline and glycyl-prolyl-hydroxyproline, contain amino acid sequences known to occur frequently in the collagen molecule (7). To further implicate collagen breakdown as the source of urinary hydroxyproline peptides are the observations that excretion increases or decreases in a number of clinical conditions where an increase or decrease in collagen breakdown would be expected (8)(9)(10)(11). INTRODUCTIONUrinary hydroxyproline peptide excretion would be most useful in the analysis of diseases of connective tissues at the clinical level if it represents a quantitatively significant and fairly constant fraction of the hydroxyproline released by collagen degradation. Since urinary hydroxyproline excretion is almost entirely in the form of peptides, its quantitative importance would appear to depend on what proportion of the peptides released by the degradation of collagen is excreted in urine, what proportion is further degraded to carbon dioxide, and whether this is a fairly constant relationship.The present investigation approaches the question of the quantitative significance of urinary hydroxyproline peptide excretion by techniques similar to those used in the study of plasma proteins (12, 13). Known quantities of radioactive hydroxyproline peptides were administered to unlabeled animals and the distribution of excretion in urine, respiratory carbon dioxide, and feces was measured. This approach permits an estimation of the quantitative significance of each of these pathways from the distribution of excretion of radioactivity. The Journal of Clinical Investigation Volume 48 1969 1These s...

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“…Pro-Hyp is usually the predominant hydroxyproline peptide in urine. 1,2) This peptide linkage originates from the sequence Gly-Pro-Hyp in the collagen molecule that has escaped complete proteolysis. 3) Gelatin, a heat-denatured product of collagen, is widely utilized as a foodstuff in the food industry, and in folk medicines in China and Europe.…”

mentioning

confidence: 99%

Absorption of Hydroxyproline-Containing Peptides in Vascularly Perfused Rat Small Intestinein Situ

Liu

Sugita

Nihei

et al. 2009

Bioscience, Biotechnology, and Biochemistry

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Urinary Hydroxyproline Peptides*

Cited by 110 publications

References 22 publications

Evidence for two different modes of tripeptide disappearance in human intestine. Uptake by peptide carrier systems and hydrolysis by peptide hydrolases.

Evidence for two different modes of tripeptide disappearance in human intestine. Uptake by peptide carrier systems and hydrolysis by peptide hydrolases.

The quantitative relationship of urinary peptide hydroxyproline excretion to collagen degradation

Absorption of Hydroxyproline-Containing Peptides in Vascularly Perfused Rat Small Intestinein Situ

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