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)

Val-D-Leu-Pro-Phe-Phe-Val-D-Leu, a specific inhibitor of aspartate proteinases of the pepsin type, was synthesized. Its bonding to activated 6-aminohexanoic acid-Sepharose 4B afforded an affinity support suitable for the purification of human, porcine, and chicken pepsin, human gastricsin, and bovine cathepsin D. These enzymes bind to the support over the pH range 2-5 at 0-1.5 M concentration of NaCl. A buffer at pH greater than or equal to 6, low ionic strength, and containing 20% dioxane can serve as a general desorption agent. The proteinases were isolated from the crude extracts by a single-step procedure in a high degree of purity and in yields exceeding 70%; human pepsin, however, was not separated from human gastricsin. The support does not show any binding capacity for rat plasma renin at pH 7.4 and for some cysteine endopeptidases (cathepsin B, H, and L) at pH 3-5. The cathepsin D preparations isolated by affinity chromatography on the new support and on pepstatin-Sepharose were of the same degree of purity as evidenced by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, N-terminal amino acid sequences, and specific activity.
...
PMID:Purification of pepsins and cathepsin D by affinity chromatography on Sepharose 4B with an immobilized synthetic inhibitor. 643 40

Cadmium metallothionein (CdMT) nephrotoxicity was studied in rats injected i.p. with a single nonlethal dose of CdMT (0.6 mg of Cd per kg). Within 8 hr of CdMT injection, urine volume and urine sodium excretion were increased and sodium dodecyl sulfate gel electrophoresis of urine proteins showed that elevated levels of low molecular weight proteins were present in the urines of CdMT-treated rats. Urine RNAase activity was also elevated, approximately 7-fold, by CdMT but not by zinc metallothionein (ZnMT) or lysozyme at equivalent protein doses, demonstrating that a proteinuria indicative of proximal tubule cell dysfunction develops as an early response to CdMT exposure. Ultrastructural alterations were also present in animals injected with CdMT but not ZnMT or lysozyme. The earliest alterations occurred in the lysosome compartment of the cell. By 1 hr, the number of small lysosomes in renal proximal convoluted tubule cells increased significantly with no changes in other organelle compartments. By 4 and 8 hr, there was a further increase in lysosome number with a concomitant decrease in size and a marked increase in the number of small clear apical vacuoles. Lysosomal cathepsin D activity was decreased at 4 and 8 hr after CdMT injection, and in vitro studies indicated that this effect was not due to a direct inhibition of the enzyme by Cd++ or CdMT. Thus, both lysosome size and protease activity were rapidly altered by CdMT exposure. Studies of Cd binding in the kidney suggest that non-MT-bound Cd is an important factor in CdMT-associated toxicity. Approximately 97% of the Cd present in the cytoplasm at 1 hr was non-MT-bound. Prior induction of renal MT by treatment with zinc (20 mg of Zn per kg as ZnSO4, i.p. 16 hr before CdMT injection) markedly reduced non-MT binding of Cd++ in kidneys of treated animals and inhibited the alterations in urine volume and low molecular weight protein reabsorption induced by CdMT. These data suggest that acute CdMT exposure provides an excellent system for studying the mechanism of cadmium tubular proteinuria and that the intracellular renal MT pool plays a key role in regulating this process.
...
PMID:Cadmium-Metallothionein nephropathy: relationships between ultrastructural/biochemical alterations and intracellular cadmium binding. 670 45

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

In this study we have shown that sodium deprivation of rats increased the number of specific granules and renin activity in atria. Sodium loading and DOCA treatment were found to lower the number of granules and renin activity. Renin activity which is present in both atria and ventricles is not localized in specific granules, as shown by ultracentrifugation and immunocytochemistry. Although this renin activity was partially abolished by preincubation with specific antiserum, the present results do not rule out the possibility that the activity is due to cathepsin D.
...
PMID:Relationship of specific granules to renin activity in the myocardium. 676 75

The enzymatic degradation of insoluble elastin has been studied at several pH values using purified pepsin and cathepsin D, and neutrophil extracts. Pepsin degraded elastin throughout the pH range of 1.2-4.0 with the optimum pH below 2.0. Molecular sieve chromatography and gel electrophoresis indicated that a spectrum of molecular weight degradation products was produced. The degradation by pepsin was inhibited by sodium dodecyl sulfate (SDS), NaCl and pepstatin. Cathepsin D, which, like pepsin, degrades hemoglobin at acid pH and is inhibited by pepstatin, had no activity against insoluble elastin in the pH range of 3.2-7.2. Extracts of neutrophils degraded elastin above pH 4.0. The pH profile of elastin degradation by neutrophil extracts generally followed that of purified human leukocyte elastase. Our results suggest that during alimentation or pulmonary aspiration of gastric contents, extracellular elastin may be digested by gastric juice at acid pH. Inflammatory cells would not appear to be capable of contributing to such actions until local pH approaches neutrality. Cathepsin D, a major constituent of inflammatory cells, does not digest all types of connective tissue proteins.
...
PMID:The enzymatic digestion of elastin at acidic pH. 678 96

Human renal renin was purified from normal kidney by either of two protocols which combined sequential DEAE-cellulose chromatography, pepstatin affinity chromatography, gel filtration, and a final step of affinity chromatography using either the synthetic octapeptide renin inhibitor (D-Leu6] or antirenin immunoglobulin as ligand. An approximate 500,000-fold purification and a yield of 1 mg of protein or 7% enzymatic activity from 10 kg were obtained by either method. Maximum specific activity was 1170 Goldblatt units/mg. Amino acid composition and kinetic properties were determined. Using purified angiotensinogen substrate, optimum pH was 5.5-6.0 and the Km was 1.54 X 10(-6) M. Two major forms of renin possessing similar enzymatic and immunologic properties, but differing in apparent molecular size and charge were purified and characterized. One form, the major form obtained after antibody affinity chromatography, had an apparent molecular size of 50 kilodaltons by sodium dodecyl sulfate-gel electrophoresis and migrated more slowly (RF = 0.32) on polyacrylamide disc gel electrophoresis at pH 7.8. The other form had an apparent molecular size of 39 kilodaltons and migrated more rapidly (RF = 0.76) on polyacrylamide disc gels. This smaller form predominated in protocols which allowed the persistent presence of acid protease activity throughout purification. Moreover, renin molecular size was demonstrated to change from 50 to 40 kilodaltons in the presence of this protease, which was subsequently isolated from the penultimate step of renin purification and tentatively identified as a renal cathepsin D. These findings help reconcile certain disparate characteristics for pure human renin obtained by others, explain the marked instability of the human enzyme, and suggest that the apparent molecular size of human renin is somewhat larger than had been previously reported.
...
PMID:Pure human renin. Identification and characterization and of two major molecular weight forms. 679 May 33

Cathepsin D inactivated aldolase at pH values between 4.2 and 5.2; the chloride, sulphate or iodide, but not citrate or acetate, salts of sodium or potassium accelerated the rate of inactivation. Cathepsin D cleaved numerous peptide bonds in the C-terminus of aldolase, but the major site of cleavage in this region was Leu354-Phe355. The most prominent peptide products of hydrolysis were Phe-Ile-Ser-Asn-His-Ala-Tyr and Phe-Ile-Ser-Asn-His. Up to 20 amino acids were removed from the C-terminus of aldolase, but no further degradation of native aldolase was observed. By contrast, extensive degradation of the 40 000-Mr subunit was observed after aldolase was denatured. The cathepsin D-inactivated aldolase cross-reacted with antibodies prepared against native aldolase and had the same thermodynamic stability as native aldolase, demonstrated by differential scanning calorimetry and fluorescence quenching of tryptophan residues. Furthermore, the cathepsin-modified and native forms of aldolase were both resistant to extensive proteolysis by other purified cellular proteinases and lysosomal extracts at pH values of 4.8-8.0.
...
PMID:Action of cathepsin D on fructose-1,6-bisphosphate aldolase. 688 56

Extrarenal renin has been a subject of considerable interest. Chiefly, studies have focused on brain and vascular renin activity in large arteries. A method now exists for the isolation from the cerebrum of microvascular tissues consisting of arterioles, capillaries and venules. The present study has demonstrated reninlike enzymatic activity within the cerebral microvasculature of the rat that is distinct from plasma renin activity. Maximal activity was observed at pH 4.5 with no measurable activity at pH 7.4. Activity with homologous renin substrate was only 13% of that measured with hog substrate whereas a 400-fold increase in reninlike specific activity was observed when microvessel homogenates were incubated with synthetic tetradecapeptide renin substrate. Bilateral nephrectomy did not affect microvascular reninlike activity. Pepstatin 15 nM, abolished reninlike activity in microvessel homogenates. Mean specific microvessel reninlike activity was 1.15 +/- 0.20 pg angiotensin I . microgram protein-1 . h-1 in control animals. Neither sodium depletion nor DOC-saline administrations caused a significant change in microvascular reninlike activity. It is suggested that the reninlike activity observed in microvessels is an acid protease, perhaps cathepsin D derived from lysosomes.
...
PMID:Reninlike enzymatic activity in the cerebral microvessels of the rat. 698 71

Two types of cathepsin D (cathepsins D-I and D-II) were purified from rhesus monkey lung to homogeneity as judged from disc gel electrophoresis. Cathepsin D-I was purified about 2,000-fold with a 5.1% yield while cathepsin D-II was purified about 2,300-fold with a 14.3% yield. Both cathepsins D were rich in the lysosome fraction of the lung, but appeared to be present in part extracellularly. Both showed a molecular weight of about 35,000 on Sephadex G-100 chromatography, and about 41,000 on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Cathepsin D-I showed the maximal activity on bovine hemoglobin and albumin at pH 3.4 and 4.0, respectively. It was most stable in the pH range of 5 to 7, but was rather unstable outside this pH range. Cathepsin D-II was quite similar in properties to that from Japanese monkey lung (Moriyama, A. & Takahashi, K. (1978) J. Biochem. 83, 441-451), and was remarkably stable in the pH range of 1-9. Under the conditions used, it retained at least 80% of the original activity when incubated at 37 degrees C for 20 h in this pH range. This stability seems to allow cathepsin D-II to be fairly active even at pH 1.0. Both cathepsins D acted on protein substrates fairly similarly and hydrolyzed hemoglobin most rapidly among the proteins tested. They did not hydrolyze N-acetyl-L-phenylalanyl-3,5-diiodotyrosine. Upon incubation with the oxidized B-chain of insulin, both cathepsins D hydrolyzed the Ala-Leu, Leu-Tyr, Tyr-Leu, Phe-Phe, and Phe-Tyr bonds at both pH 3.0 and 5.0. In addition, cathepsin D-II hydrolyzed the Leu-Val and Tyr-Thr bonds at pH 3.0 and the Val-Asn bond at pH 5.0. Both cathepsins D were inactivated by acid protease-specific inhibitors such as pepstatin, 1,2-epoxy-3-(p-nitrophenoxy)propane, p-bromophenacyl bromide, and diazoacetyl-DL-norleucine methyl ester, although cathepsin D-II was much less susceptible to these reagents except p-bromophenacyl bromide.
...
PMID:Cathepsins D from rhesus monkey lung. Purification and characterization. 699 76

We have obtained evidence of thiol endopeptidases in the thyroid which are active in thyroglobulin degradation in vitro. Four pepstatin-insensitive endopeptidase fractions were distinguished in extracts of rabbit thyroids by gel filtration on Bio-Gel A-0.5m. An enzyme from one fraction was obtained in highly purified form and was found to be identical to cathepsin B described in other tissues. Endopeptidases in the three remaining fractions were designated as cathepsins 180K, 110K, and 45K, respectively, on the basis of their estimated molecular size. These were partially purified by either organomercurial affinity chromatography or DEAE-cellulose chromatography. They are identified as thiol endopeptidases on the basis of their sensitivity to inhibition by both leupeptin and the thiol-blocking agent iodoacetic acid and by their activation with the reducing agent glutathione. Each is distinguished from cathepsin B on the basis of molecular size and limited ability to hydrolyze benzoylarginine-2-naphthylamide. The action of the thiol endopeptidases on [125I]thyroglobulin was analyzed by polyacrylamide gel electrophoresis in sodium dodecyl sulfate or in sodium dodecyl sulfate and urea. In each instance, the initial peptide fragments were approximately 40-45K and 30K, with iodothyronine contents similar to or less than that of intact thyroglobulin. Later products of digestion than that of intact thyroglobulin. Later products of digestion included first, 20K peptides, which showed a low iodothyronine content, and finally, peptides of approximately 10K, which showed a 1.5-fold enrichment of T4 and T3 over that of intact thyroglobulin. Each of the thiol endopeptidases had a synergistic effect when incubated with cathepsin D and [125I]thyroglobulin. Among the products of such incubations were small iodopeptides, which were iodothyronine-enriched, and free T4, itself. The results show that thiol endopeptidases are present in the thyroid gland and are collectively as important as cathepsin D in the hydrolysis of thyroglobulin in vitro. The action of these enzymes must be considered along with that of cathepsin D in understanding thyroglobulin hydrolysis in vivo.
...
PMID:Thyroglobulin degradation by thyroidal proteases: action of thiol endopeptidases in vitro. 704 63


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

---