A method for determining amino acid concentrations and specific activities of amino acids and some other compounds in biological fluids

✍ Scribed by Neelakantan Vaidyanath; Ronald Birkhahn; John R. Border; Rapier McMenamy; Garret Oswald; Gregory Trietley; Tran F. Yuan

• Publisher: Elsevier Science
• Year: 1976
• Tongue: English
• Weight: 710 KB
• Volume: 70
• Category: Article
• ISSN: 0003-2697
• DOI: 10.1016/0003-2697(76)90473-5

✦ Synopsis

A method is described for obtaining plasma ultrafiltrates from which the concentrations of all amino acids, including tryptophan and ammonia, are obtained. A split-stream methodology is described for obtaining, in addition to the concentrations, the radioactivities of amino acids, glucose, and plasma water.

A number of methods for determining the free amino acid concentrations in plasma and other biological fluids have been reported. Typically, the methods have involved sulfosalicylic acid or picric acid to obtain protein-free supernatant solutions for the analysis (1-3). Extractions with these reagents generally give erroneous values for glutamine, glutamate, and tryptophan.

We have further developed a technique used earlier, that of centrifugal ultrafiltration (4), to obtain ultrafiltrates from which concentrations of all amino acids, including those above mentioned as well as ammonia, can be determined directly by a resin column technology. Included is a description of the use of split stream system for simultaneously determining the concentrations of amino acids and radioactivities of amino acids and some other compounds eluted from the column.