Beta-Aminoisobutyric Acid, A Possible Factor in Pyrimidine Metabolism.

Abstract

The unknown substance previously reported ( 1 ) as a major ninhydrin-reacting component in a number of urine chromatograms, particularly in those of patients with malignancy, has now been isolated from the urine of a normal subject(2) and 2 cancer patients and identified as beta-aminoisobutyric acid (BMB). Preliminary animal experiments indicate that its precursor is a 5 -methylpyrimidine, Experimental. Isolation and identification of beta-aminoisobutyric acg. Urine samples from cancer patients were collected in bottles containing thymol and stored in the fareezer. When several specimens containing high concentrations of the unknown compound had been collected from a single patient they were pooled and fractionated in ion-exchange columns. The large variety and high concentrations of extraneous substances in urine made the fractionation more difficult than in the case of protein hydrolysates(3), but ion exchange 'appears to be the method of choice for separating the small quantity of amino acids in urine from the much larger quantity of strong electrolytes and non-electrolytes. Generally, our best results were obtained as follows: The urine was diluted 2-fold or more,

FAMILY STUDIES ON THE URINARY EXCRETION OF SS-Aminoisobutyric ACID

“…The frequency of 9.6 yo found above corresponds quite well with the results of Fink et al (1951), who found in a series of 140 people, 11 individuals having a ratio of B-aminoisobutyric acid to alanine in their urine greater than 2. Their estimates were based on the measurement of the intensity of the colour developed in their chromatograms, and they state that the ninhydrin reaction on paper under the conditions they were using was approximately half as sensitive for P-aminoisobutyric acid as for most of the other amino-acids, so that their criterion was very much the same as that used here.…”

“…Subsequently it was isolated from urine and its chemical constitution determined (Crumpler, Dent, Harris & Westall, 1951). These findings were later entirely confirmed by Fink, Henderson & Fink (1951). The amount of this substance present in the urines of different people appears, as judged by the intensity and size of the spots formed in chromatograms, to vary considerably.…”

A direct quantitative paper chromatography of amino acids and its application to the urinary excretions of some human ethnic groups

“…Frequency distributions of ,B-aminoi8obutyric acid the rest, are in conformity with earlier evidence excretion rates in the three ethnic groups. 0, Chinese; /, (for brief review see (Fink et al 1951), 9.6% (Harris, 1953) and 102 % (Allison, Blumberg & Gartler, 1959). The incidence is clearly low, and the lack of a 'higher' excretor in the present small European sample is not contrary to expectations.…”

“…With reference to (iii), although there is evidence (Fink, Henderson & Fink, 1951) that the excretion of f-aminoi8obutyric acid by the rat is subject to the effects of endogenous (dietary) factors, these are believed to play a negligible role in normal human subjects maintained on normal diets. Within-sample distributions of values recorded in Table 2 are shown in Fig.…”

THE EXCRETION OF β‐AMINOISOBUTYRIC ACID FOLLOWING THYMINE AND DIHYDROTHYMINE ADMINISTRATION TO MAN

“…It is imknown how the body handles these isomers in absorption and metabolism. The BAIB isolated from the urine of human subjects by Crumpler, Dent, Harris and Westall (1951), Fink (1951), and Fink, Henderson and Fink (1951), was laevorotatory as was that found in iris bulbs by Asen, Thompson, Morris and Irreverre (1959). Whether D-BAIB results from D-DHT, and how the kidney would handle D-BAIB, is not known.…”