Peptides in Human Urine

Abstract

Peptiduria is a physiological phenomenon. The total amount of peptides excreted in urine and the qualitative composition of these compounds showed variations even in normal subjects, and these marked qualitative and quantitative differences can be observed in certain pathological conditions. Quantitative determination of peptides in urine, determination of amino acids liberated in the course of total hydrolysis of urine, determination of amino acid content of certain nitrogen fractions isolated from urine, examination of low-molecular weight peptides isolated from urine, and isolation of polypeptides contained in urine are the methods of identification of peptides present in urine. The chapter presents the results of studies on amino acids liberated after complete hydrolysis of urine, amino acids liberated in the course of the hydrolysis of certain peptide fractions isolated from urine, raised level of some peptides in pathological urine, single peptides isolated from normal and pathological urine, and homogeneous peptide groups isolated from normal urine. Some fraction of the peptides appearing in urine represents small quantities of peptide hormones. Investigations in the field of physiological and pathological peptiduria have a brilliant future. Further methodological advances in the development of uniform and standardized procedures for determination of peptides in urine are necessary before this trend of research gains an established position in clinical chemistry.