Specific Antiserum and Monoclonal Antibodies Against the Taurine Biosynthesis Enzyme Cysteine Sulfinate Decarboxylase: Identity of Brain and Liver Enzyme

Abstract

Cysteine sulfinate decarboxylase (CSD), the putative biosynthetic enzyme for taurine, was purified 1,800-fold with a 1% yield from rat liver, where it was found to be 20-fold enriched compared with brain. The final fraction was homogeneous, as ascertained through sodium dodecyl sulfate-polyacrylamide gel electrophoresis and reverse-phase HPLC. An antiserum was raised in the rabbit that (a) quantitatively immunoprecipitated CSD activity and (b) immunolabeled only one band (MW = 51,000) on an immunoblot from liver homogenate. Monoclonal antibodies were also raised that recognized the CSD protein and immunolabeled the same 51-kilodalton protein on an immunoblot from liver homogenate. In a brain extract, two CSD activities had been previously found and named CSDI and CSDII, according to their chromatographic elution patterns. We have compared the properties of CSDI from brain--the most likely enzyme involved in the biosynthesis of taurine in the brain, according to previous investigations-and CSD from liver: Both activities (a) were similarly eluted on ion-exchange and hydroxyapatite chromatographies, (b) showed the same elution pattern on gel filtration with an apparent native molecular weight of approximately 63,000, and (c) were immunoprecipitated in a strictly identical manner by the antiserum against liver CSD. Moreover, this antiserum as well as the monoclonal antibodies immunolabeled a single band (51 kilodaltons) on an immunoblot from brain CSD-enriched fraction or liver fraction. All these data show that CSDI from brain and liver CSD are the same monomeric enzyme. They also indicate that a specific antiserum against rat liver CSD has been raised that can be used for immunocytochemical visualization of CSD-containing cells in the brain.

Taurine immunoreactivity in the rat supraoptic nucleus: Prominent localization in glial cells

“…Taurine and CSAD have been detected via immunocytochemistry in various regions of the brain using different antibodies (Chan-Palay et al, 1982;Madsen et al, 1985;Ottersen et al, 1985;Campistron et al, 1986;Yoshida et al, 1986;Ida et al, 1987;Magnusson et al, 1988;Remy et al, 1990;Pirvola and Panula, 19921, revealing an important variability in the patterns of labeling obtained. In contrast to the cerebellum, cortex, and caudate-putamen, where labeling was mainly neuronal, the hypothalamus displayed a predominant glial taurine-like immunoreactivity (Storm-Mathisen and Ottersen, 1986;Madsen et al, 1987).…”

Expression of Cysteine Sulfinate Decarboxylase mRNA in Rat Mammary Gland.

“…Their nature is now fully elucidated, and the previously called CSDII was shown to be an enzymatic activity expressed by glutamate decarboxylase (GAD), the biosynthetic enzyme of γ-aminobutyric acid (GABA) [9]. On the basis of kinetic, biochemical and immunochemical data [9,12], the previously called CSDI was demonstrated to be identical to the CSD found in the liver and is thus henceforth called simply CSD.In the present study, to validate our hypothesis mentioned above, we investigated the expression of CSD mRNA in the mammary gland of lactating rats by means of RT-PCR and in situ hybridization. …”

Identification and expression of cysteine sulfinate decarboxylase, possible regulation of taurine biosynthesis in Crassostrea gigas in response to low salinity

“…Remy, et al . 38 found two copies of CSAD in brain and liver of mouse, respectively, and functions of them was similar. Although CSAD gene is the key enzyme in taurine biosynthesis pathway and the key to maintain cellular taurine balance, the two copies of CSAD in C. gigas have different expression patterns in response to low salinity.…”