Determination of S-Carbamyl Group in Biological Materials

A sensitive and simple method for the determination of acid soluble and acid insoluble S -carbamyl groups in biological materials is presented. This method is based on the chemical properties of the S -carbamyl group, which is stable in acidic solution and liberates cyanate in alkaline solution, and those of the cyanate analyzer reported previously. Each sample solution was mixed with 20%(w/v) trichloroacetic acid (TCA) solution; the mixture was incubated for 1 h at 37°C, followed by centrifugation. For the determination of acid soluble S -carbamyl group, the supernatant was added to an equal volume of 1.0M NaOH. Liberated cyanate was determined by cyanate analyzer. For the determination of acid insoluble S -carbamyl group, the precipitate was washed twice with 7%(w/v) TCA solution and then dissolved in 1.0 M NaOH. After ultrafiltration, cyanate in filtrate was determined. The usefulness and practicality of the present method were verified by applications to the determination of S -carbamyl group in liver, plasma and erythrocytes of mouse.