PRODUCTION AND CHARACTERIZATION OF A NEW SPECIFIC ANTISERUM AGAINST THE TAURINE PUTATIVE BIOSYNTHETIC ENZYME CYSTEINE SULFINATE DECARBOXYLASE

We have shown previously that cysteine sulfinate decarboxylase (CSD), the putative biosynthetic enzyme of taurine in the brain, is identical to the liver enzyme according to biochemical, kinetic, and immunochem ical criteria. In the present work, CSD was purified in its native for m from rat liver. The purification was performed in eight steps, which included conventional chromatography (diethylaminoethyl cellulose, hy droxylapatite), followed by HPLC (hydrophobic, adsorption, and ion-exc hange HPLC). The purification factor was 11,000, and the final yield w as around 2%. The procedure led to the enrichment of a protein, the mo lecular mass of which was 51,000 daltons as determined by sodium dodec yl sulfate-polyacrylamide gel electrophoresis. The final fraction was more than 90% homogeneous. By using this fraction as the antigen, an a ntiserum was raised in rabbit that (a) quantitatively immunoprecipitat ed CSD activity from liver and brain extract, and (b) immunolabeled on e band (51,000 daltons) on immunoblots of partially purified fractions from liver. Enrichment of CSD specific activity and that of the prote in immunolabeled by the antiserum for a given step, e.g., hydrophobic HPLC, were consistently parallel. The antiserum was used to carry out CSD immunocytochemistry in cerebellum. Numerous small cells were label ed in the Purkinje cell layer, the granular layer, and the white matte r. In the molecular layer, Bergmann radial fibers were immunostained. The Purkinje and stellate cells were devoid of any labeling at the cel l body and terminal levels. The antiserum appears to be specific for C SD and suitable for immunocytochemical visualization of CSD in the bra in.