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

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

1. Growing rats were fed either ad lib. or with six (equal) meals offered every 4 h (from 10.00 hours). Rats of each group were killed at intervals of 4 h beginning at 11.00 hours. Activities of cathepsin A (carboxypeptidase A; EC 3.4.12.2), C (dipeptidyl peptidase; EC 3.4.14.1) and D (endopeptidase D EC 3.4.23.5) were measured in liver and muscle homogenates and free amino acids in blood were determined. 2. In the rats fed ad lib. activities of carboxypeptidase A and endopeptidase D in liver and muscle showed significant variation, with maximum activity in the light period. In general, meal-feeding only caused minor differences in cathepsin activities; although significant differences occurred for carboxypeptidase A. For the later enzyme a peak in activity occurred in the dark as well as in the light period. 3. Irrespective of the feeding schedule, the lower concentration of free essential amino acids of blood occurred generally during the night period. With the controlled-feeding schedule there is an increase of essential amino acids and a slight decrease of non-essentail amino acids of blood.
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PMID:Variations through the day of hepatic and muscular cathepsin A (carboxypeptidase A; EC 3.4.12.2), C (dipeptidyl peptidase; EC 3.4.14.1) and D (endopeptidase D; EC 3.4.23.5) activities and free amino acids of blood in rats: influence of feeding schedule. 719 24

The activity of cathepsin A, cathepsin D and other enzyme-markers of liver damage (ASPAT, ALAT, GGTP, LDH, AP) were measured in the serum of persons acutely intoxicated with ethanol and chronic alcoholics. Persons acutely intoxicated with ethanol had the unchanged activity of cathepsin A and cathepsin D while it increased in the chronic alcoholic serum.
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PMID:The activity of cathepsin A and cathepsin D in the serum of persons acutely intoxicated with ethanol and chronic alcoholics. 852 92

To investigate the intracellular transport mechanisms of lysosomal cathepsin D in yeast cells, we produced cathepsin D in Saccharomyces cerevisiae by placing the coding region under the control of the promoter of the yeast glyceraldehyde-3-phosphate dehydrogenase (GAPDH) gene. Immunoblotting analysis by the use of an antibody specific for rat cathepsin D coding sequence produced an intermediate species which had a slightly higher molecular weight than that of the mature cathepsin D. Cell fractionation experiments demonstrated that the cathepsin D polypeptide was colocalized to the yeast vacuoles with the marker enzyme carboxypeptidase Y in a Ficoll step gradient. A biosynthesis study with pulse-chase kinetic analysis revealed that the precursor polypeptide was accurately sorted to the yeast vacuoles as determined by cell fractionation, and that N-linked carbohydrate modifications were not required for vacuolar sorting of this protein. To elucidate the role of the propeptide region of cathepsin D, which might function in the intracellular targeting to the vacuole, a deletion mutant of cathepsin D lacking the propeptide was prepared and its intracellular targeting was examined after transfection into yeast cells. Immunoblotting analysis demonstrated that the propeptide-deleted mutant protein was recovered in a low quantity as compared with that in the case of yeast cells expressing the wild-type protein in the isolated vacuolar fraction. Immunofluorescence analysis revealed that the deletion mutant protein appeared to be accumulated within the intracellular small vesicles but not in the carboxypeptidase Y-positive vacuoles. Overall, these results indicate that the rat cathepsin D precursor polypeptide is recognized by mechanisms similar to those involved in the intracellular sorting of vacuolar proteins through the ER/Golgi/vacuolar sorting pathway in yeast cells, and that the propeptide has an important function in translocation of the cathepsin D polypeptide to the vacuole.
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PMID:Expression of rat cathepsin D cDNA in Saccharomyces cerevisiae: implications for intracellular targeting of cathepsin D to vacuoles. 853 7

Mannose 6-phosphate (Man-6-P) is a posttranslational carbohydrate modification typical of newly synthesized acid hydrolases that signals targeting from the Golgi apparatus to the lysosome via Man-6-P receptors (MPRs). Using iodinated cation independent MPR as a probe in a Western blot assay, we surveyed levels of Man-6-P glycoproteins in a number of different rat tissues. Considerable variation was observed with respect to total amounts and types of Man-6-P glycoproteins in the different tissues. Brain contained 2-8-fold more Man-6-P glycoproteins than other tissues, with relative abundance being brain >> testis approximately heart > lung approximately kidney approximately ovary approximately spleen > skeletal muscle approximately liver approximately serum. Analysis of 16 different lysosomal enzyme activities revealed that brain contains lower activities than other tissues which suggested that decreased removal of Man-6-P results in increased levels of Man-6-P glycoproteins. This was directly demonstrated by comparing activities of phosphorylated lysosomal enzymes, purified by immobilized MPR affinity chromatography, with total activities. The phosphorylated forms accounted for a considerable proportion of the MPR-targeted activities measured in brain (on average, 36.2%) but very little in lung, kidney, and liver (on average, 5.5, 2.3, and 0. 7%, respectively). Man-6-P glycoproteins were also isolated from rat brain by MPR affinity chromatography on a preparative scale. Of the 18 bands resolvable by SDS-polyacrylamide gel electrophoresis, seven bands were NH2-terminally sequenced and identified as the known lysosomal enzymes cathepsin L, cathepsin A, cathepsin D, alpha-galactosidase A, arylsulfatase A, and alpha-iduronidase. One of the major Man-6-P glycoproteins was identified as palmitoyl protein thioesterase, which was not previously thought to be lysosomal. This finding raises important questions about the cellular location and function of palmitoyl protein thioesterase, mutations in which result in the neurodegenerative disorder, infantile neuronal ceroid lipofuscinosis.
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PMID:Rat brain contains high levels of mannose-6-phosphorylated glycoproteins including lysosomal enzymes and palmitoyl-protein thioesterase, an enzyme implicated in infantile neuronal lipofuscinosis. 870 98

A key step in the targeting of soluble lysosomal enzymes is their recognition and phosphorylation by a 540 kDa multisubunit enzyme, UDP-N-acetylglucosamine-phosphotransferase (phosphotransferase). The molecular mechanism of recognition is still unknown, but previous experiments suggested that the phosphotransferase-binding sites on lysosomal proteins are represented by structurally conserved surface patches of amino acids. We identified four such regions on nonhomologous lysosomal enzymes, cathepsins A, B, and D, which were superimposed by rotating their structures around the Calpha atom of the glycosylated Asn residue. We proposed that these regions represent putative phosphotransferase-binding sites and tested synthetic peptides, derived from these regions on the basis of surface accessibility, for their ability to inhibit in vitro phosphorylation of purified cathepsins A, B, and D. Our results indicate that cathepsin A and cathepsin D have one closely related phosphotransferase recognition site represented by a structurally and topologically conserved beta-hairpin loop, similar to that previously identified in lysosomal beta-glucuronidase. The most potent inhibition of phosphorylation was demonstrated by homologous peptides derived from the regions located on cathepsin molecules opposite the oligosaccharide chains which are phosphorylated by the phosphotransferase. We propose that recognition and catalytic sites of the phosphotransferase are located on different subunits, therefore, providing an effective mechanism for binding and phosphorylation of lysosomal proteins of different molecular size.
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PMID:Identification of UDP-N-acetylglucosamine-phosphotransferase-binding sites on the lysosomal proteases, cathepsins A, B, and D. 989 Aug 84

We describe the identification, cDNA cloning, and biochemical characterization of a new human blood plasma glutamate carboxypeptidase (PGCP). PGCP was co-purified from human placenta with lysosomal carboxypeptidase, cathepsin A, lysosomal endopeptidase, cathepsin D, and a gamma-interferon-inducible protein, IP-30, using an affinity chromatography on a Phe-Leu-agarose column. A PGCP cDNA was obtained as an expressed sequence tag clone and completed at 5'-end by rapid amplification of cDNA ends polymerase chain reaction. The cDNA contained a 1623-base pair open reading frame predicting a 541-amino acid protein, with five putative Asn glycosylation sites and a 21-residue signal peptide. PGCP showed significant amino acid sequence homology to several cocatalytic metallopeptidases including a glutamate carboxypeptidase II also known as N-acetyl-aspartyl-alpha-glutamate carboxypeptidase or as prostate-specific membrane antigen and expressed glutamate carboxypeptidase activity. Expression of the PGCP cDNA in COS-1 cells, followed by Western blotting and metabolic labeling showed that PGCP is synthesized as a 62-kDa precursor, which is processed to a 56-kDa mature form containing two Asn-linked oligosaccharide chains. The mature form of PGCP was secreted into the culture medium, which is consistent with its intracellular localization in secretion granules. In humans, PGCP is found principally in blood plasma, suggesting a potential role in the metabolism of secreted peptides.
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PMID:Purification, cDNA cloning, and expression of a new human blood plasma glutamate carboxypeptidase homologous to N-acetyl-aspartyl-alpha-glutamate carboxypeptidase/prostate-specific membrane antigen. 1020 90

The epithelial cells lining the cauda epididymidis and vas deferens are active in endocytosis and have an abundance of lysosomes and a well-characterized secretory apparatus. However, little is known about the nature of lysosomal proteins contained within lysosomes, the types of receptors on the cell surface, and the types of proteins secreted by these cells. In the present study, cathepsins A, D, B, and sulfated glycoprotein (SGP)-1, well-characterized lysosomal proteins, as well as SGP-2, a secretory protein and low-density lipoprotein receptor-related protein-2 (LRP-2), an endocytic receptor, were immunolocalized at the light-microscopic level within epithelial cells of the cauda epididymidis and vas deferens. Principal cells showed numerous intensely reactive lysosomes for cathepsins A, D, and SGP-1 in all regions of the cauda and vas deferens and for cathepsin B only in the cauda epididymidis. Basal cells were intensely reactive for cathepsin A, unreactive for cathepsins D and B, and weakly reactive for SGP-1 in the cauda region. In the vas deferens, these cells were intensely reactive for cathepsin A and SGP-1 and unreactive for cathepsin B; in the case of cathepsin D, basal cells were weakly reactive in the proximal vas deferens but intensely reactive in the middle and distal vas deferens. Clear cells, present in the cauda region and proximal vas deferens, were intensely reactive for cathepsin A, weakly reactive for SGP-1, and unreactive for cathepsins D and B, while narrow cells found mainly in the proximal vas deferens were intensely reactive for cathepsins A, D, and SGP-1 and unreactive for cathepsin B. Thus, the expression of different lysosomal enzymes in the cauda epididymidis and vas deferens is not only cell- but also region-specific, suggesting differences in the type of substrates internalized by these cells. SGP-2, a secretory protein, showed a checkerboardlike staining pattern in the cytoplasm of principal cells of the cauda epididymidis, while the cytoplasm of all principal cells were intensely reactive in the vas deferens. This type of reaction, as well as staining of sperm, suggests that SGP-2 is secreted into the lumen, where it functions in relation to sperm. The endocytic receptor LRP-2 was noted only on the apical surface of principal cells of the cauda and vas deferens and in spherical structures indicative of endosomes suggestive of their role in the uptake of various ligands, including SGP-2, for which it has a high binding affinity. Thus SGP-2 in the cauda and vas deferens is not only secreted but endocytosed by principal cells, suggestive of an active turnover in the lumen. In summary, the epithelial cells of the cauda and vas deferens show marked differences in expression of lysosomal proteins, SGP-2, and LRP-2 suggestive of differences in their functional activity while sperm are stored and protected in these regions.
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PMID:Cell- and region-specific localization of lysosomal and secretory proteins and endocytic receptors in epithelial cells of the cauda epididymidis and vas deferens of the adult rat. 1038 22

1. Cerebral proteinases were separated on Sephadex G-100 columns into acid and neutral fractions free from cross-contamination. Acid proteinases were more stable and were purified by additional steps with salt and pH5.0 precipitations, column chromatography on DEAE- or CM-cellulose and free-flow electrophoresis. 2. The separation made it possible to study the properties of the partially purified enzyme fractions. Some of these properties, such as K(m) with selected protein substrates, pH optima and temperature-dependence in the presence and absence of substrates, are described. 3. No requirement for metal ions or added cofactors was demonstrated. Neutral-proteinase activity was more sensitive to inhibition by heavy-metal ions; its activity could be increased by thioglycollate and glutathione, and inhibited by thiol reagents. Neutral and acid proteinases were inhibited by the chymotrypsin inhibitor chloromethyl l-2-phenyl-1-toluene-p-sulphonamidoethyl ketone. 4. In the presence of the appropriate synthetic substrates no cathepsin A activity was found, and only trace quantities of cathepsin B or C activities, which were more than 50-fold less than cathepsin D-like activity.
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PMID:Separation of acid and neutral proteinases of brain. 1674 27

Tripeptidyl-peptidase I (TPPI) is an acidic lysosomal peptidase that removes tripeptides from an unmodified N-terminus of small proteins and polypeptides. In humans, TPP I constitutes an integral part of the lysosomal proteolytic apparatus, which, includes numerous hydrolytic enzymes, mostly cysteine proteases (cathepsin B, C, H, K, L, and others), but also serine (cathepsin A) and aspartic (cathepsin D) proteases. The combination of endo- and exopeptidase activities of these enzymes allows for efficient digestion of the diverse proteins transported to the lysosomes, releasing free amino acids and dipeptides that are transported back to the cytoplasm and reused according to the metabolic needs of the cell. The role of TPP I in normal lysosome functioning is underscored by the genetic association of the enzyme with one form of a group of the developmental neurodegenerative disorders of childhood--the neuronal ceroid lipofuscinoses (NCLs). The scope of this article is to review the most recent data, mostly from author's laboratory, on the biology and pathology of TPP I. NCLs are also shortly reviewed with the special emphasis on CLN2 form resulting from mutations in TPP I gene.
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PMID:[Tripeptidyl-peptidase I--distribution, biogenesis, and mechanisms of activation]. 1686 97

Lysosomes are intracellular organelles which contain enzymes and activator proteins involved in the digestion and recycling of a variety of cellular and extracellular substances. We have identified a novel sorting receptor, sortilin, which is involved in the lysosomal trafficking of the sphingolipid activator proteins, prosaposin and GM(2)AP, and the soluble hydrolases cathepsin D, cathepsin H, and acid sphingomyelinase. Sortilin belongs to a growing family of receptors with homology to the yeast Vps10 protein, which acts as a lysosomal sorting receptor for carboxypeptidase Y. In this study we examined the effects of the sortilin gene inactivation in mice. The inactivation of this gene did not yield any noticeable lysosomal pathology. To determine the existence of an alternative receptor complementing the sorting function of sortilin, we quantified the concentration of prosaposin in the lysosomes of the nonciliated epithelial cells lining the efferent ducts. These cells were chosen because they express sortilin and have a large number of lysosomes containing prosaposin. In addition, the nonciliated cells are known to endocytose luminal prosaposin that is synthesized and secreted by Sertoli cells into the seminiferous luminal fluids. Consequently, the nonciliated cells are capable of targeting both exogenous and endogenous prosaposin to the lysosomes. Using electron microscope immunogold labeling and quantitative analysis, our results demonstrate that inactivation of the sortilin gene produces a significant decrease of prosaposin in the lysosomes. When luminal prosaposin was excluded from the efferent ducts, the level of prosaposin in lysosomes was even lower in the mutant mice. Nonetheless, a significant amount of prosaposin continues to reach the lysosomal compartment. These results strongly suggest the existence of an alternative receptor that complements the function of sortilin and explains the lack of lysosomal storage disorders in the sortilin-deficient mice.
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PMID:The inactivation of the sortilin gene leads to a partial disruption of prosaposin trafficking to the lysosomes. 1973 68


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