DETERMINATION OF GLUTAMINE AND GLUTAMIC ACID IN THE BLOOD PLASMA OF CHICKS BY A COMBINED CHROMATOGRAPHIC AND MICROBIOLOGICAL METHOD

Abstract

Glutamine was separated from glutamic acid by chromatographing deproteinized plasma on a 10-cm column of Dowex 1X8 and by eluting with acetate buffer, pH 4.2. The first portion of eluate, which contained the glutamine but no glutamic acid, was subjected to microbiological assay using Lactobacillus plantarum as a test organism. Recovery of glutamine added to plasma was satisfactory and the precision of the assays conducted was within 4%. Several substances were found to interfere with the microbiological assay but these were eliminated by the chromatographic procedure. The method was extended to the determination of glutamic acid by continued elution of the column with acetate buffer, pH 4.2, fractionation of the eluate, and determination with ninhydrin. Average glutamine and glutamic acid contents of plasma of normal non-fasting chickens were 12.8 and 3.4 mg per 100 ml respectively.