Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.24.11 (CD10)
 9,792 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Two proteolytic enzymes capable of releasing the angiotensin I-converting enzyme (ACE) inhibitor Ile-Pro-Pro from casein were identified by purification of an Aspergillus oryzae extract by three-step column chromatography. First, proteins capable of producing Ile-Pro-Pro from beta-casein were eluted using a DEAE-sepharose FF column with a linear sodium chloride gradient. An endopeptidase capable of releasing Pro-Ile-Pro-Gln-Ser-Leu-Pro-Gln-Asn-Ile-Pro-Pro from Pro-Ile-Pro-Gln-Ser-Leu-Pro-Gln-Asn-Ile-Pro-Pro-Leu-Thr-Gln and an aminopeptidase producing Ile-Pro-Pro from Gln-Asn-Ile-Pro-Pro were separated from the resultant fraction using a hydroxyapatite column. Each active enzyme was then loaded onto a Develosil 300Diol gel filtration column for high performance liquid chromatography (HPLC) and purified to homogeneity. The endopeptidase had a molecular mass of approximately 46,000 Da and exhibited an N-terminal amino acid sequence identical to that of neutral protease I (NP I) of A. oryzae. Meanwhile, the aminopeptidase had a molecular mass of 36,000 Da and an N-terminal amino acid sequence similar to that of Leucine aminopeptidase (LAP), as reported in Aspergillus sojae and A. oryzae. The eluted endopeptidase and aminopeptidase were thus identified as NP I and LAP, respectively. Analysis of peptide production using synthetic proteins containing an Ile-Pro-Pro sequence showed that NP I processed the C-terminal end and LAP processed the N terminus to produce Ile-Pro-Pro. While Ile-Pro-Pro was successfully produced from casein by the addition of these two purified enzymes, it was not generated with the addition of only a single enzyme. Based on our experimental findings, we suggest that NP I and LAP are key proteolytic enzymes in the release of Ile-Pro-Pro from casein in A. oryzae.
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PMID:Purification and identification of proteolytic enzymes from Aspergillus oryzae capable of producing the antihypertensive peptide Ile-Pro-Pro. 1944 37

To determine the cellular localization of nervous tissue peptidases, 7 peptidases and 2 lysosomal marker enzyme activities were measured in cultured mouse and rat cells. Neuronal cells of both species exhibited higher activities of angiotensin-converting enzyme (ACE) and prolyl endopeptidase (Pro-EP) than glial cells did. In contrast, arginyl endopeptidase and lysosomal enzymes (acid phosphatase, ?-glucuronidase) in the neuronal cell lines were lower than those in the glial cell lines. Other peptidases (alanyl aminopeptidase, arginyl aminopeptidase, leucyl aminopeptidase, dipeptidyl aminopeptidase) activities were not specifically localized in either cell lines. The effects of cellular differentiation on these peptidase activities in the PC 12h cell line and rat glioblasts were also examined using nerve growth factor (NGF) and glia maturation factor (GMF), respectively. Neuron specific peptidase (ACE and Pro-EP) activities were decreased in PC12h cells cultured with NGF, and Pro-EP activity was increased in the glioblast cells cultured with GMF. These results support the idea that some of the peptidases are differentially localized in neuronal or glial cells, and play physiological roles in central or peripheral neural tissues.
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PMID:Localization of angiotensin-converting enzyme, prolyl endopeptidase and other peptidases in cultured neuronal or glial cells. 2049 7

The phenotypes of the human renal epithelial cell lines, SK-NEP-1 and G401 (Wilm's tumour lines) and ACHN, A498, A704, Caki-1 and Caki-2 (renal adenocarcinomas), were investigated in order to develop as toxicological model systems, human renal cell lines showing properties similar to those found in discrete renal tubular segments. All cell lines, except G401, demonstrated significant (P < 0.05) stimulation of adenyl cyclase activity by calcitonin. Alkaline phosphatase activity was not detectable in any cell line except for G401. None of the cell lines tested was capable of forming epithelial layers characteristic of 'tight' epithelia. The G401 cell line displayed several characteristics of the proximal nephron including a receptor for hPTH and detectable levels of the brush-border enzymes alkaline phosphatase (0.18 +/- 0.02 mU/mg protein), leucine aminopeptidase (14.0 +/- 5.1 mU/mg protein), glutathione transferase (8.61 +/- 2.53 mU/mg protein) and gamma-glutamyl transpeptidase (24.0 +/- 2.1 mU/mg protein). hPTH (0.01-1 mum) stimulated adenyl cyclase activity in homogenates of G401 cells in a dose-dependent manner, and this stimulation was reversed by 10 mum of the specific PTH antagonist Nle, Tyr-PTH 3-34 amide. The addition of 10 mum antagonist to unstimulated G401 cell homogenate reduced the basal activity of adenyl cyclase from 87.3 +/- 17.4 to 45.9 +/- 13.2 pmol cAMP/mg protein . 15 min. The effect of known nephrotoxic agents was tested on G401 cells by measuring basic mitochondrial enzyme function (MTT assay). The antibiotic gentamicin (5 mm), significantly (P < 0.001) inhibited MTT activity in a dose-dependent manner with a maximum inhibition to23.2 +/- 9.2% of untreated G401 cells. S- (1,1,2,2,tetrafluoroethyl)- l -glutathione (4 mm) and its cysteine conjugate (2.5 mm) reduced MTT activity to 44.0 +/- 10.9% and 33.3 +/- 2.6% of control untreated G401 cells, respectively. We suggest that the G401 cell line may be a useful model of the human proximal tubule in predictive toxicology.
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PMID:Established human renal cell lines: Phenotypic characteristics define suitability for use in in vitro models for predictive toxicology. 2073 80

Proteins constitute a particularly bioavailable subset of organic carbon and nitrogen in aquatic environments but must be hydrolyzed by extracellular enzymes prior to being metabolized by microorganisms. Activities of extracellular peptidases (protein-degrading enzymes) have frequently been assayed in freshwater systems, but such studies have been limited to substrates for a single enzyme [leucyl aminopeptidase (Leu-AP)] out of more than 300 biochemically recognized peptidases. Here, we report kinetic measurements of extracellular hydrolysis of five substrates in 28 freshwater bodies in the Delaware Water Gap National Recreation Area in the Pocono Mountains (PA, United States) and near Knoxville (TN, United States), between 2013 and 2016. The assays putatively test for four aminopeptidases (arginyl aminopeptidase, glyclyl aminopeptidase, Leu-AP, and pyroglutamyl aminopeptidase), which cleave N-terminal amino acids from proteins, and trypsin, an endopeptidase, which cleaves proteins mid-chain. Aminopeptidase and the trypsin-like activity were observed in all water bodies, indicating that a diverse set of peptidases is typical in freshwater. However, ratios of peptidase activities were variable among sites: aminopeptidases dominated at some sites and trypsin-like activity at others. At a given site, the ratios remained fairly consistent over time, indicating that they are driven by ecological factors. Studies in which only Leu-AP activity is measured may underestimate the total peptidolytic capacity of an environment, due to the variable contribution of endopeptidases.
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PMID:Potential Activities of Freshwater Exo- and Endo-Acting Extracellular Peptidases in East Tennessee and the Pocono Mountains. 2955 61


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