Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

---

Query: EC:3.4.23.5 (cathepsin D)
4,130 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Cathepsin D was purified about 1000-fold from human brain cortex by a procedure involving ammonium sulfate fractionation (30-70%), Sephadex G-75 chromatography, affinity chromatography on pepstatin-Sepharose and isoelectric focusing. The enzyme was assayed fluorometrically at pH 3.2, the substrates used were globin or haemoglobin modified with pyridoxal-5'-phosphate. 6 multiple forms of cathepsin D were resolved in the isoelectric focusing step with pI values 4.4, 4.8, 5.3, 6.2, 6.5 and 6.8. Km of pyridoxal-globin and pyridoxal-haemoglobin for all 6 multiple forms is 1.8-2.0 X 10(-5) M and 1.3 to 4 X 10(-6) M, respectively, and Ki of pepstatin is 2-4 X 10(-9) M. Gel filtration of the multiple forms on Sephadex G-100 column showed that each has a molecular weight of about 50 000. Human brain cathepsin D has a pH optimum of 3.2 with a smaller second optimum at pH 4.0 (pyridoxal-haemoglobin being used as substrate). All the multiple forms have the same pH-dependence curve. On SDS-polyacrylamide gel electrophoresis the purified enzyme produced 3 bands approximately corresponding to Mr 50 000, 35 000 and 15 000. Study of the breakdown of substance P and its C-terminal heptapeptide by cathepsin D shows that cleavage occurs at the Phe-Phe linkages of both substrates tested.
...
PMID:Cathepsin D from human brain: purification and multiple forms. 667 69

The purification of cathepsin D from pig uterus by two-step affinity chromatography on concanavalin A- and pepstatin-Sepharose was described previously [Afting & Becker (1981) Biochem. J. 197, 519-522]. In this paper, chemical and physical properties of the proteinase are presented. The purified enzyme showed three bands on SDS (sodium dodecyl sulphate)/polyacrylamide-gel electrophoresis, one main band corresponding to an Mr of 31 000 and two minor bands with Mr values of 43 000 and 15 000 respectively. Gel filtration on Bio-gel P-150 and sedimentation-diffusion equilibrium studies give an Mr for the main band of about 35 000. The pI of the enzyme was determined to be 7.2. Haemoglobin was the best substrate, with a Km value of 6.4 X 10(-6)M. It was hydrolysed with a pH optimum between 3.0 and 3.3 for a substrate concentration of 100 microM. The proteinase was stable over the pH range of 3.5-6.5. At pH 6 the enzyme showed stability up to a temperature of 50 degrees C; at pH 3 the activity was already decreased below 40 degrees C. Carbohydrate studies resulted in the staining of all three bands on an SDS/polyacrylamide gel by thymol/H2SO4. After treatment with endo-beta-N-acetylglucosaminidase H, all three bands were shifted to a region of lower Mr. Of various inhibitors tested, only pepstatin was strongly inhibiting, with a Ki of 2.1 X 10(-9)M.
...
PMID:Cathepsin D from pig myometrium. Characterization of the proteinase. 674 51

Leucocytes contain an urokinase inhibitor, that can be inactivated by cathepsin D. In this work biochemical and immunological studies on the inactivation of this inhibitor by cathepsin D are presented. Examinations by polyacrylamide gel electrophoresis and SDS electrophoresis indicate that cathepsin D inactivates urokinase inhibitor by hydrolysis of the inhibitor molecule and that the degradation needed for total inactivation is different from that for formation of the precipitin line with antibodies. The conversion of active inhibitor into inactive protein proceeds catalytically.
...
PMID:Inactivation studies of the leucocyte inhibitor of urokinase by cathepsin D. 678 39

The mode of degradation of myofibrillar proteins by the action of highly purified rabbit muscle cathepsin D (EC 3.4.23.5) was studied using SDS-polyacrylamide gel electrophoresis. Cathepsin D optimally degraded myosin heavy chain, alpha-actinin, tropomyosin, troponin T and troponin I at around pH 3. It did not degrade actin or troponin C. Degradation of myosin heavy chain produced four major fragments of 155000, 130000, 110000 and 90000 daltons. Troponin T was hydrolyzed to 33000-, and 20000- and 11000-dalton fragments. Troponin I was degraded into fragments of 13000 and 11000 daltons. Degradation of alpha-actinin and tropomyosin was not as rapid as that of myosin and troponins T and I. Tropomyosin gave a fragment of 30000 daltons, but alpha-actinin showed no distinct band of this fragment on gels.
...
PMID:Mode of degradation of myofibrillar proteins by rabbit muscle cathepsin D. 682 29

Human placental cathepsin D has been purified 6000-fold and its properties characterized. Its molecular weight has been ascertained to be 42 000 by gel filtration and 43 300 by analytical ultracentrifugation. SDS gel electrophoresis in the presence of beta-mercaptoethanol cleaves the enzyme into two polypeptides of molecular weights 28 200 and 14 400. The placental enzyme resembles cathepsin D isolated from other mammalian tissues in many of its properties, including pH optimum. The higher degree of purification has led to a shift in the isoelectric points of the three isoenzymes from those recorded by other authors. Antibodies raised against cathepsin D in rabbits inhibit it at pH 5.0, and the inhibition is almost 100 per cent with adequate concentrations of monospecific antibody.
...
PMID:Purification and properties of human placental cathepsin D. 707 39

More than 95% of the apparent cathepsin D activity in the lysosomes of porcine adrenal cortex was due to a genuine cathepsin D that has a molecular weight of 42,800 +/- 800 (mean +/- standard deviation of the mean in 5 runs) as determined by Sephadex G-100 column chromatography. On CM-Sephadex C-50 column chromatography at pH 6.9, the enzyme was resolved into five peaks which were termed Fractions D1 through D5 in order of their elution from the column. Fraction D4 and Fraction D5 together constituted more than 70% of the total cathepsin D, and were purified through chromatographic procedures to constant specific activities. The content of lysosomal cathepsin D was estimated to be about 1% of the total cellular protein. On isoelectric focusing, Fraction D4 was resolved into one major band with pI of 7.34 (termed Form D4-1) and one minor band of 7.20 (Form D4-2), while Fraction D5 gave one major band with pI of 7.50 (Form D5-1) and two minor ones of 7.37 (Form D5-2) and of 7.20 (Form D5-3). All of these 5 bands were enzymatically active. On SDS-polyacrylamide gel electrophoresis, both Form D4-1 and Form D5-1 dissociated into three subunits with molecular weights of 27,400 +/- 500 (termed Subunit A), 24,600 +/- 400 (Subunit B) and 13,800 +/- 600 (Subunit C) (mean +/- standard deviation of the mean in 16 determinations). The three subunits all contained carbohydrates.
...
PMID:Characterization of cathepsin D in porcine adrenocortical lysosomes. 711 74

Cathepsin D (EC 3.4.23.4) was purified from rabbit skeletal muscle using acetone-dried muscle powder as starting material. After the acetone-dried powder was extracted with 0.2 mM ATP, the extract was fractionated with acetone an subjected to DEAE-Sephadex A-50 and Sephadex G-100 column chromatography. Rechromatography on a Sephadex G-100 column resulted in a purified preparation. SDS-polyacrylamide gel electrophoresis of the purified enzyme showed one major band of 42,000 daltons and some bands of contaminants. Since gel filtration also indicated a value of 42,000 daltons for the enzyme, it was concluded that muscle cathepsin D has no subunit structure. The enzyme acted optimally towards myofibrils around pH3, resulting in the degradation of the myosin heavy chain and production of a 30,000-dalton component.
...
PMID:Purification of cathepsin D from rabbit skeletal muscle and its action towards myofibrils. 731 36

The biosynthesis and turnover of rat liver NADH-cytochrome b(5) reductase was studied in in vivo pulse-labeling and long-term, double-labeling experiments. Rats under thiopental anesthesia were injected into the portal vein with [(3)H]L-leucine and sacrificed at various times after the injection. NADH-cytochrome b(5) reductase was extracted from liver cell fractions by cathepsin D-catalyzed cleavage and was then immunoadsorbed onto antireductase-bearing affinity columns in the presence of excess unlabeled rat serum. After elution of the enzyme from the columns with a pH-2.2 buffer, the amount of the reductase protein in the samples was determined by radioimmunoassay, and the radioactivity in reductase was determined on SDS polyacrylamide gel reductase bands. The specific radioactivity of the reductase extracted from the homogenate as well as from rough and smooth microsomal, mitochondrial, and Golgi fractions, estimated at the end of the pulse (10 min after the injection) and at various time points thereafter, remained approximately constant over a 6-h period. These data suggest tha tth eenzyme is independently inserted into the various membranes where it is located. Moreover, the specific radioactivity of the mitochondrial reductase was lower than that of the other fractions, suggesting that it turns over at a slower rate. The lower turnover rate of the mitochondrial enzyme was confirmed by long-term, double-labeling experiments carried out according to the technique of Arias et al. (J. Biol. Chem. 244: 3303-3315.). The relevance of these findings in relation to the understanding of membrane biogenesis and turnover is discussed.
...
PMID:Localization and biosynthesis of NADH-cytochrome b5 reductase, an iontegral membrane protein, in rat liver cells. III. Evidence for the independent insertion and turnover the enzyme in various subcellular compartments. 741 81

Proteolytic modification of circulating insulin-like growth factor binding protein-3 (IGFBP-3) has been described in a number of conditions. Using Western ligand blotting and SDS-PAGE analysis of fragmentation patterns of 125I-labelled IGFBP-3 and 125-labelled IGFBP-1, we have examined conditioned media from cultured human cell lines for the presence of proteolytic activity and compared this with the action of circulating proteases and with characterized enzymes including cathepsin D, kallikrein, plasmin and tissue plasminogen activator. 125I-Labelled IGFBP-3 was incubated with serum from pregnant women, patients following heart surgery and patients with cancer of the breast, lung or head/neck. Following separation of the preincubated samples by SDS-PAGE, a distinct pattern of degradation fragments was observed which was similar in all cases. This proteolytic activity was inhibited in the presence of EDTA, phenanthroline and 4(-2-aminoethyl)-benzenesulphonylfluoride, HCl. These proteases had no detectable effect on IGFBP-1. Serum-free conditioned medium from a human dermal fibroblast cell line, a rabdomyosarcoma, a cervical, a bladder, a chorio- and two-tongue squamous cell carcinoma cell lines all contained proteolytic activity which fragmented IGFBP-3. The pattern of fragments was similar in all cell lines but different from that produced by the circulating proteases. Six out of nine cell lines produced protease(s) which degraded IGFBP-1 in addition to IGFBP-3. Whilst all the characterized enzymes tested also fragmented IGFBP-3 and plasmin cleaved IGFBP-1, none of these acted in the same way as either circulating or cell line-derived proteolytic activity. The activity associated with the characterized enzymes and cell lines was inhibited in the presence of serum from normal healthy subjects. These results demonstrate that the serum of pregnant women, post-operative patients and patients with cancer contain circulating proteases which cause fragmentation of IGFBP-3 but have little effect on IGFBP-1. Cell-derived proteases were shown to act on IGFBP-3 and IGFBP-1 in a number of instances but are not active in the presence of circulating inhibitors. These proteases may play an important role in regulating the availability of IGFs to normal and neoplastic tissues.
...
PMID:Proteolytic modification of insulin-like growth factor-binding proteins: comparison of conditioned media from human cell lines, circulating proteases and characterized enzymes. 750 92

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.
...
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


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>

---