Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.4.99.7 (sialyltransferase)
 1,534 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have developed a method for the isolation of the subcellular organelles from bovine liver which are enriched in the cation-independent mannose 6-phosphate receptor (CI-MPR) and the cation-dependent mannose 6-phosphate receptor (CD-MPR). The purification scheme consists of sedimentation of a postnuclear supernatant fraction on a sucrose gradient followed by immunoisolation using specific anti-peptide antibodies conjugated to magnetic polystyrene beads. Antibodies that recognize the cytoplasmic domain of either the CI-MPR or the CD-MPR routinely give membrane preparations that are approximately 50-fold enriched in each of the respective receptors, as determined by quantitative Western blotting. The immunoisolated membranes are also enriched in the other MPR, as well as in the asialoglycoprotein receptor. They contain significantly lower levels of enzyme activities representative of the plasma membrane (5' nucleotidase) or the Golgi complex (galactosyltransferase and sialyltransferase). There is little or no enrichment for either the lysosomal enzymes beta-hexosaminidase and tartrate-resistant acid phosphatase, or the mitochondrial enzyme succinate-tetrazolium reductase. These data, together with electron microscopy of the immunoisolated material, suggest that the bulk of MPR-containing membranes we have isolated from bovine liver correspond to endosomes. Analysis by SDS-PAGE indicates that several proteins, including two with apparent molecular weights of 170 K and 400 K, are significantly enriched in the purified fractions and may represent potential markers for MPR-containing endosomes.
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PMID:Isolation and characterization of membranes from bovine liver which are highly enriched in mannose 6-phosphate receptors. 254 3

The present investigation was performed in order to elucidate the subcellular localization of angiotensin-converting enzyme (ACE) in human alveolar macrophages. A pure population of alveolar macrophages was obtained by centrifugal elutriation of bronchoalveolar lavage (BAL) fluid from seven sarcoid patients. The cells were homogenized by sonication and the postnuclear supernatant was fractionated on a discontinuous sucrose gradient. Fractions of particulate material were collected and characterized by marker enzymes. The distribution pattern of ACE closely resembled that of NADPH-cytochrome-c-reductase and sialyltransferase, markers of the endoplasmic reticulum and the Golgi complex, respectively, indicating a common localization. This localization is compatible with synthesis taking place in the alveolar macrophage.
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PMID:Subcellular localization of angiotensin-converting enzyme in the human alveolar macrophage. 303 14