Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.23.5 (cathepsin D)
 4,130 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Plasma very-low density lipoprotein (VLDL) and vitellogenin (VTG) from mature female Japanese quail (Coturnix coturnix japonica) and chickens (Gallus domesticus) were isolated and digested in vitro with cathepsin D (EC3.4.23.5). The incubation mixtures were then reduced and subjected to gradient (4.5-18%) SDS-polyacrylamide gel electrophoresis. Protein fragments were stained with either Coomassie Brilliant Blue R-250 (VLDL digests) or Coomassie Brilliant Blue R-250 containing 20 mM AlCl3 (VTG digests). Fragments resulting from the in vitro enzymatic digestion of quail and chicken plasma VLDL-apolipoprotein B (apo B) and VTG closely resembled those produced in vivo and isolated from egg yolks of each respective species. Phosvitin, a proteolytically derived fragment of VTG, primarily existed as a single band (M(r) approximately 42 kDa) in Japanese quail yolk granules. In contrast, chicken phosvitin mainly consisted of a cluster of phosphoproteins ranging in size from approximately 37 to 45 kDa. In addition to reporting a novel species difference in phosvitin moieties, the present study is the first to examine the role of cathepsin D in the generation of egg yolk proteins from plasma precursors in Japanese quail. Confirmatory evidence also was provided concerning the important role of this aspartic endopeptidase in the proteolytic cleavage of plasma VLDL-apo B and VTG in the chicken.
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PMID:Proteolysis of Japanese quail and chicken plasma apolipoprotein B and vitellogenin by cathepsin D: similarity of the resulting protein fragments with egg yolk polypeptides. 758 50

Chicken vitellogenin, a serum lipoprotein specific for laying hens, has been thought to be proteolytically cleaved into the heavy and light chain lipovitellins and phosvitin, the major yolk granule proteins, during or after transportation into oocyte. In this study, another proteolytic product of vitellogenin has newly been isolated from the 'beta-livetin' fraction of yolk plasma. It is a yolk glycoprotein of 40 kDa (YGP40) with asparagine-linked carbohydrate chain(s) recognized by Concanavalin A and castor bean lectin (RCA-I), and it is identified as a C-terminal cysteine-rich fragment of the major vitellogenin (vitellogenin II), the cysteine-rich domain homologous to D2 region of von Willebrand factor. Another yolk plasma glycoprotein of 42 kDa is suggested to be one of the proteolytic products of the minor vitellogenin (vitellogenin I). Both 40 kDa and 42 kDa glycoproteins were shown to be present in growing oocytes but absent in laying hen's serum. Limited proteolysis of vitellogenin II with cathepsin D produced a 40 kDa protein with reactivity to anti-YGP40 antibody. Gel filtration analysis of vitellogenin II digested with cathepsin D showed that YGP40 dissociated from lipovitellin-phosvitin complex after the proteolytic cleavage. These results suggest that after incorporation from serum via a specific receptor vitellogenin II is cleaved in the oocyte into four fragments, heavy and light chain lipovitellins, phosvitin and YGP40, and that YGP40 is released into the yolk plasma before or during compartmentation of lipovitellin-phosvitin complex into the yolk granule.
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PMID:Precursor-product relationship between chicken vitellogenin and the yolk proteins: the 40 kDa yolk plasma glycoprotein is derived from the C-terminal cysteine-rich domain of vitellogenin II. 759 59

A pepstatin A-sensitive enzyme involved in yolk formation was purified from the masu salmon (Oncorhynchus masou) ovary using in vitro generation of yolk proteins from purified vitellogenin to assay enzymatic activity. Purification of the enzyme involved precipitation of ovarian extracts by water and ammonium sulfate followed by five steps of column chromatography. After SDS-PAGE and Western blotting, the purified enzyme appeared as a single approximately 42 kDa band that was immunoreactive to anti-human cathepsin D. The course of proteolytic cleavage of the three major yolk proteins (lipovitellin, beta'-component, and phosvitin) in fertilized masu salmon and Sakhalin taimen (Hucho perryi) eggs and embryos was visualized by SDS-PAGE and Western blotting using specific antisera. Major yolk protein bands appeared in positions corresponding to 92 kDa, 68 kDa, and 22 kDa (lipovitellin-derived peptides), as well as 17 kDa (beta'-component). During embryo development, the 92 kDa and 22 kDa bands gradually decreased in intensity, becoming undetectable in alevins. The 68 kDa band and a minor 24 kDa band became more intense after the eyed stage. Two additional peptides, corresponding to 40 and 28 kDa, newly appeared in alevins. During embryonic growth, the beta'-component band (17 kDa) persisted and phosvitin appeared to be progressively dephosphorylated. In vitro analysis of lipovitellin proteolysis indicated that the enzyme involved is a Pefabloc SC-sensitive serine protease. These results demonstrate, for the first time, that a cathepsin D-like protease and serine proteases play key roles in yolk formation and degradation, respectively, in salmonid fishes.
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PMID:Identification and characterization of proteases involved in specific proteolysis of vitellogenin and yolk proteins in salmonids. 1175 18

Three complete cDNAs encoding different forms of vitellogenin (Vtg) were isolated from a white perch (Morone americana) liver cDNA library and characterized with respect to immunobiochemical and functional features of the three Vtgs and their product yolk proteins (YPs) in this species and in the congeneric striped bass (Morone saxatilis). The two longest cDNAs encoded Vtgs with a complete suite of yolk protein domains that, based on comparisons with vtg sequences from other species, were categorized as VtgAa and VtgAb using the current nomenclature for multiple teleost Vtgs. The shorter cDNA encoded a Vtg that lacked a phosvitin domain, had a shortened C-terminus, and was categorized as VtgC. Mapping of peptide sequences from the purified Vtgs and their derived YPs to Vtg sequences deduced from the cDNAs definitively identified the white perch VtgAa, VtgAb, and VtgC proteins. Detailed comparisons of the primary structures of each Vtg with partial or complete sequences of Morone yolk proteins or of Vtgs from other fishes revealed conserved and variant structural elements of teleost Vtgs with functional significance, including, as examples, signal peptide cleavage sites, dimerization sites, cathepsin D protease recognition sites, and receptor-binding domains. These comparisons also yielded an interim revision of the classification scheme for multiple teleost Vtgs.
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PMID:Conserved and variant molecular and functional features of multiple egg yolk precursor proteins (vitellogenins) in white perch (Morone americana) and other teleosts. 1876 2