MICROASSAY METHODS FOR TAURINE AND CYSTEINE SULFINATE DECARBOXYLASE ACTIVITY

Abstract

Microassay methods for taurine (2-aminoethanesulfonic acid) and cysteine sulfinate decarboxylase (CSD: EC 4.1.1.29) were developed. Cation exchange resin (Dowex 50W .times. 8, 200-400 mesh) was used for the separation of taurine from other fluorescamine reactive substances. The taurine fraction in this column chromatographic procedure was collected fluorescence development was carried out. The maximal sensitivity obtained for taurine was 25 pmol. The specificity, reproducibility, sensitivity and recovery for taurine obtained by this method were satisfactory enough to be used for biological applications. The activity of CSD was determined by measuring the formation of 14CO2 from DL-[1-14C]-cysteine sulfinic acid using a specially designed micro-vessel. The activity in rat cerebral tissues containing 5 .mu.g of protein was accurately detected by this microradiometrical method. Using above microassay methods for taurine and CSD activity, the rat spinal cord, taurine is distributed rather evenly, whereas the distribution of CSD activities is uneven and the highest activity is localized at the dorsal part of the dorsal horn.