Peptide analysis as amino alcohols by gas chromatography-mass spectrometry. Application to hyperoligopeptiduria. Detection of Gly-3Hyp-4Hyp and Gly-Pro-4Hyp-Gly

Dipeptide analysis in human urine

Fractions of dipeptides, obtained from human urine by a combination of cation-exchange chromatography, ligand-exchange chromatography and reversed-phase chromatography, were transformed into their N-heptafluorobutyryl methyl ester derivatives and then subjected to capillary gas chromatography. The profiles obtained indicate the presence of many dipeptides in human urine. For the first time, alpha-Asp-Hyp, Pro-Phe and gamma-Glu-Phe were detected in the urine of healthy individuals.

Gas chromatography of amino acids in urine and haemofiltrate

Capillary gas chromatography of amino acid derivatives obtained from biological material shows a large number of previously unknown constituents. The profiles of amino acids obtained from urine of healthy individuals and haemofiltrate of uraemic patients indicate that haemofiltration removes some amino acids to a considerably higher extent from uraemic patients than the kidney does from healthy persons. For instance, if haemofiltration is required three times a week, an approximately ten-fold amount of the essential amino acid methionine and a forty-fold amount of the essential amino acid leucine is lost compared to their excretion in urine by a healthy individual over the same period.

Polymorphism of urinary 4-hydroxyproline-containing polypeptides

Using molecular sieve chromatography on Bio-Gel P-2 and then on Bio-Gel P-30, hydroxyproline-containing urinary polypeptides (molecular weight greater than 1500 daltons) were separated into eight fractions. The three main fractions were separated further on phosphocellulose giving seven, nineteen and twelve peaks, respectively, each containing 4-hydroxyproline. Hypotheses about the origin of certain polypeptides are proposed, which take into account the sequence of type I collagen. Among these 38 polypeptides only one shows a quantitative variation in Paget's bone disease and was thus purified. It consists of equal amounts of glycine, proline and 4-hydroxyproline. This particular polypeptide may originate from the N-terminal propeptide of type I collagen.

A case of an exceptionally high level of urinary-4-hydroxyproline containing polypeptides

The determination of total urinary-4-hydroxyproline in an adolescent showed a very high excretion of hydroxyproline containing peptides: 26.2 mmol/24 h. Estimation of total urinary 3-hydroxyproline and peptide fractionation on Biogel P 2 demonstrated unusual features. Such cases are of great interest for structural studies of the urinary polypeptides and understanding of collagen catabolism.