Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.5.1.52 (PNGase F)
 1,527 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The biosynthesis and processing of a lysosomal cysteine proteinase, cathepsin C (dipeptidylaminopeptidase I), was investigated by pulse-chase experiments in cultured rat macrophages. Cathepsin C is first synthesized as procathepsin C with a molecular mass of 55 kDa. Procathepsin C is then cleaved and modified within 1 h into mature cathepsin C with two chains of 25 and 7.8 kDa. A combination of pulse-chase experiments and the subcellular fractionation analysis showed that procathepsin C and cathepsin C are located in low-buoyant-density organelles and lysosomes, respectively. The reactivity of endoglycosidase H and N-glycanase and analysis of phosphorylation indicated that both precursor and mature cathepsin C are phosphorylated and N-glycosylated to give a high-mannose-type. The addition of 300-kDa mannose 6-phosphate receptor antiserum to the chase medium caused extensive release of procathepsin C into the medium, whereas the addition of control serum did not. The membrane association of procathepsin C was tested by successive extraction of cells pulse labeled for 75 min with hypotonic buffer, alkaline solution, and Triton X-100. Procathepsin C was totally extracted by hypotonic solution, whereas procathepsin D was a membrane-associated form requiring Triton X-100 for its extraction. Gel-filtration chromatography analysis of the pulse-labeled products revealed that the precursor product exists as an oligomeric form. It is suggested that the oligomerization of cathepsin C occurs before its entry into lysosomes.
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PMID:Processing and transport of the precursor of cathepsin C during its transfer into lysosomes. 821 89

Mammalian alpha-fucosidase (EC 3.2.1.51) is a lysosomal enzyme that catalyzes the removal of fucose residues from glycosphingolipids and its absence in humans results in a rare metabolic disorder called fucosidosis. Among the invertebrates in the molluscs (Unio) two forms of the enzyme have been reported, a 68 kDa non-glycosylated form and a 56 kDa glycosylated form. The glycosylated form has been purified from the seminal fluid of Unio [Biochem. Biophys. Res. Commun. 234 (1997) 54]. In the present study, the 56 kDa glycosylated form has been purified to homogeneity from the whole body tissue of Unio using a series of chromatographic steps. The purified enzyme migrated as a single protein species in 10% SDS-PAGE. Antibodies to the purified enzyme were raised in a rabbit in order to study its biochemical and immunological properties. The purified enzyme is a glycoprotein that exhibits strong binding to Con A-Sepharose gel and can be deglycosylated by PNGase F enzyme suggesting it to be N-glycosylated. The enzyme has been shown to specifically interact with the mannose 6-phosphate receptor protein (MPR 300) purified from goat and Unio. This specific interaction is discussed in view of its possible in vivo binding partners.
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PMID:Biochemical and immunological characterization of a glycosylated alpha-fucosidase from the invertebrate Unio: interaction of the enzyme with its in vivo binding partners. 1535 48