SOME NINHYDRIN-POSITIVE SUBSTANCES IN THE PLASMA AND URINE OF THE DOG

Abstract

The dog has been used for much research into various aspects of metabolic and physiological functions, including many studies in the field of amino acids, yet little has been published concerning the pattern of free amino acids in the dog's plasma and urine, and even less on the peptides and other ninhydrin-positive substances. The separation and identification of a number of these ninhydrin-positive substances were carried out by means of three two-dimensional electrophoretic and (or) chromatographic systems and the application of specific and generalized tests for different amino compounds.The amino acids known to be present in the plasma and urine of humans along with α-aminoadipic acid and homocitrulline were also found in those of dogs except for phosphoethanolamine, δ-aminolevulinic acid, α-aminovaieric acid, sarcosine, and glucosamine. The peptides detected in the urine of the dog were anserine, carnosine, cystathionine, α-aspartylglycine, β-aspartylglycine, β-aspartylhistidine, β-aspartylvaline, α-glutamylleucine, γ-glutamylleucine, glycylaspartic acid, and glycylproline. Of these peptides only anserine, carnosine, and α-aspartylglycine could normally be detected in the plasma.