Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.4.37 (CNPase)
 539 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Stationary phase cultures of a clonal line of rat astrocytes (C6) were maintained at pH values ranging from 6.0 to 8.4 using media buffered with various combinations of organic buffers or graded concentrations of bicarbonate ion at a constant CO2 tension. The accumulation of a soluble acidic protein unique to the nervous system (S-100) in media buffered with organic buffers was optimal in the pH range 6.4 to 6.8, significantly more acid than that optimal for cell growth (pH 7.0 to 7.8). Cells maintained in CO2-bicarbonate-buffered media exhibited a higher and less marked pH optimum for S-100 protein accumulation and a lower efficiency of accumulation of the protein. These data suggest that the organic buffer ions themselves, apart from their function as buffers, are influencing the accumulation of S-100. The specific activity (assayed at the enzymatic pH optimum) of a membrane-bound enzyme enriched in glial cells and myelin, 2',3'-cyclic nucleotide 3'-phosphohydrolase, was markedly pH-dependent. The optimal pH range was 6.4 to 6.7 in organic buffer controlled media. In CO2-bicarbonate controlled media the optimal pH range was only slightly higher (pH 6.6 to 7.0), but the specific activities were reduced relative to organic buffer-grown cells. The structural relationship of some of the aminoethanesulfonic acid buffers used in these experiments to certain compounds of neurochemical interest (such as taurine and alpha-flupenthixol) is noted.
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PMID:Effect of ethanesulfonic acid buffers and pH on the accumulation of a nervous system-specific protein (S-100) and a glial-enriched enzyme in a clonal line of rat astrocytes (C6). 0 54

The activity of calcium-activated neutral proteinase (mM CANP) was determined in subcellular fractions of rat brain. The CANP activity in whole homogenate and its membrane fractions including myelin was increased ten-fold following treatment with Triton X-100. The majority of the activity (60%) was in the primary particulate fractions P1 (nuclear), P2 (mitochondrial), and P3 (microsomal). Following subfractionation of each particulate fraction, most of the activity (50%) was found in the myelin-enriched fractions (P1A, P2A, and P3A) and separated at the interface of 0.32-0.85 M sucrose. Only 20-30% of the total homogenate activity was in cytosol. The enrichment in the myelin fractions resembled that for 2',3'-cyclic nucleotide 3'-phosphohydrolase (CNPase) activity. Immunoblotting revealed that the CANP was mainly in myelin and cytosol. In addition to the presence of 72-76 Kd and 80 Kd bands, there were faint high-molecular-weight CANP bands ranging from 110-150 Kd and lower-molecular-weight forms in the region of 30-50 Kd in both purified myelin and cytosol. These studies suggested that CANP is present in myelin and cytosol and that it exists in the brain in membrane-bound and soluble forms.
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PMID:Calcium-activated neutral proteinase in rat brain myelin and subcellular fractions. 285 61

We have extended our studies on the content of white matter derived coated vesicles (WMCVs) to show that they are enriched in membrane-bound carbonic anhydrase. Within the myelin complex membrane-bound carbonic anhydrase is concentrated in the periaxolemmal domain; however, this protein is enriched almost sevenfold in the bilayer of coated vesicles even relative to this myelin membrane region. These data suggest that some vesicles are derived from a site at which this enzyme is highly localized. The enrichment observed for membrane-bound carbonic anhydrase is unique since other periaxolemmal proteins such as CNPase and plasmolipin are only present in equal amounts in periaxolemmal-myelin fractions and WMCVs. Based on their known localization, the presence of CNPase coupled with the absence of MAG in WMCVs suggest that these vesicles are derived from the paranodal region. The identification in WMCVs of periaxolemmal-myelin proteins associated with ion and fluid movement, such as carbonic anhydrase, Na+,K+ ATPase, and the putative K+ channel protein plasmolipin, prompted us to examine the status of these vesicles in triethyl tin (TET)-induced myelin edema. Coated vesicles and other membrane fractions were isolated from whole brains of control and TET-treated rats. Whole brains were used so we could compare the effects of TET on WMCV proteins with the effect on proteins enriched in gray matter coated vesicles. The results indicated that TET had no detectable effect on compact or periaxolemmal-myelin, however, Western blot analysis showed that WMCV proteins, such as carbonic anhydrase, CNPase, and plasmolipin, were virtually absent or greatly diminished from the whole brain coated vesicle fraction.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Identification of membrane-bound carbonic anhydrase in white matter coated vesicles: the fate of carbonic anhydrase and other white matter coated vesicle proteins in triethyl tin-induced leukoencephalopathy. 851 Jan 85