scholarly journals A member of the eukaryotic subtilisin family (PC3) has the enzymic properties of the type 1 proinsulin-converting endopeptidase

1992 ◽  
Vol 285 (2) ◽  
pp. 391-394 ◽  
Author(s):  
E M Bailyes ◽  
K I J Shennan ◽  
A J Seal ◽  
S P Smeekens ◽  
D F Steiner ◽  
...  
Keyword(s):  
Xenopus Oocytes ◽  
Ph Optimum ◽  
Human Proinsulin ◽  
Endopeptidase Activity ◽  
Mammalian Homologue ◽  
Granule Type ◽  
Insulin Granule

PC3, a mammalian homologue of the yeast subtilisin-like proteinase Kex2, was expressed in Xenopus oocytes and its activity was characterized. PC3 cleaved human proinsulin at one of the two dibasic sites (KTRR32 but not LQKR65). The specificity, inhibitor profile, pH optimum (5.5) and Ca(2+)-dependence (K0.5 = 2.5-3 mM) paralleled those of the insulin-granule type 1 endopeptidase activity, suggesting a role for PC3 in the conversion of prohormones.

scholarly journals Certain mouse strains are deficient in a kidney brush-border metallo-endopeptidase activity

1983 ◽  
Vol 209 (1) ◽  
pp. 251-255 ◽  
Author(s):  
J S Bond ◽  
J D Shannon ◽  
R J Beynon
Keyword(s):  
Brush Border ◽  
Inbred Mice ◽  
Neutral Endopeptidase ◽  
Renal Tissue ◽  
Mouse Strains ◽  
Ph Optimum ◽  
Brush Border Enzymes ◽  
Endogenous Inhibitors ◽  
Endopeptidase Activity ◽  
Proteinase A

Preparations of microvilli from kidneys of BALB/c mice contain an alkaline metallo-endopeptidase, meprin (metallo-endopeptidase from renal tissue). Certain genealogically related inbred mice are markedly deficient in meprin activity. The meprin-deficient strains (CBA/J and C3H/HeJ) exhibit normal levels of other brush-border enzymes: alkaline phosphatase, aminopeptidase M and another proteinase, a phosphoramidon-sensitive neutral endopeptidase. Meprin deficiency cannot be attributed to a shift in pH optimum and is unlikely to be due to the presence of endogenous inhibitors.

scholarly journals Human lysosomal elastase. Catalytic and immunological properties

1976 ◽  
Vol 155 (2) ◽  
pp. 265-271 ◽  
Author(s):  
P M. Starkey ◽  
A J. Barrett
Keyword(s):  
Human Neutrophil ◽  
Serine Proteinase ◽  
Ph Optimum ◽  
Human Spleen ◽  
Pancreatic Elastase ◽  
Good Substrate ◽  
Endopeptidase Activity ◽  
Specific Antisera ◽  
Porcine Pancreatic Elastase ◽  
Effect Of Inhibitors

1. The elastase of human spleen was shown to exhibit endopeptidase activity against azo-casein and elastin. 2. Activity against several synthetic substrates was detected, and benzyloxycarbonyl-L-alanine 2-naphthyl ester was found to be a good substrate for routine use. 3. The enzyme showed a broad pH optimum in the range of 8.2-9.2 against azo-casein and the synthetic substrate. 4. The effect of inhibitors on the spleen elastase showed it to be a serine proteinase with a specificity similar to that of porcine pancreatic elastase. 5. Specific antisera were raised against the enzyme, and it was shown to be immunologically identical with the lysosomal elastase of human neutrophil leucocytes.

scholarly journals Site-directed mutations in fungal laccase: effect on redox potential, activity and pH profile

1998 ◽  
Vol 334 (1) ◽  
pp. 63-70 ◽  
Author(s):  
Feng XU ◽  
Randy M. BERKA ◽  
Jill A. WAHLEITHNER ◽  
Beth A. NELSON ◽  
Jeffrey R. SHUSTER ◽  
...  
Keyword(s):  
Redox Potential ◽  
Phenol Oxidase ◽  
Ascorbate Oxidase ◽  
Single Mutation ◽  
Redox Potentials ◽  
Wild Type ◽  
Ph Optimum ◽  
Ph Profile ◽  
Potential Activity

A Myceliophthora thermophila laccase and a Rhizoctonia solani laccase were mutated on a pentapeptide segment believed to be near the type-1 Cu site. The mutation L513F in Myceliophthora laccase and the mutation L470F in Rhizoctonia laccase took place at a position corresponding to the type-1 Cu axial methionine (M517) ligand in Zucchini ascorbate oxidase. The triple mutations V509L,S510E,G511A in Myceliophthora laccase and L466V,E467S,A468G in Rhizoctonia laccase involved a sequence segment whose homologue in ascorbate oxidase is flanked by the M517 and a type-1 Cu-ligating histidine (H512). The single mutation did not yield significant changes in the enzymic properties (including any significant increase in the redox potential of the type-1 Cu). In contrast, the triple mutation resulted in several significant changes. In comparison with the wild type, the Rhizoctonia and Myceliophthora laccase triple mutants had a phenol-oxidase activity whose pH optimum shifted 1 unit lower and higher, respectively. Although the redox potentials were not significantly altered, the Km, kcat and fluoride inhibition of the laccases were greatly changed by the mutations. The observed effects are interpreted as possible mutation-induced structural perturbations on the molecular recognition between the reducing substrate and laccase and on the electron transfer from the substrate to the type-1 Cu centre.

scholarly journals Recognition of Human Proinsulin Leader Sequence by Class I-Restricted T-Cells in HLA-A*0201 Transgenic Mice and in Human Type 1 Diabetes

Diabetes ◽  
2008 ◽  
Vol 58 (2) ◽  
pp. 394-402 ◽  
Author(s):  
A. Toma ◽  
T. Laika ◽  
S. Haddouk ◽  
S. Luce ◽  
J.-P. Briand ◽  
...  
Keyword(s):  
T Cells ◽  
Type 1 Diabetes ◽  
Transgenic Mice ◽  
Leader Sequence ◽  
Class I ◽  
Human Proinsulin ◽  
Human Type ◽  
Human Type 1 Diabetes

scholarly journals Purification and properties of a proteolytic enzyme from French beans

1965 ◽  
Vol 97 (1) ◽  
pp. 228-235 ◽  
Author(s):  
JRE Wells
Keyword(s):  
Proteolytic Enzyme ◽  
Deae Cellulose ◽  
Basic Amino Acid ◽  
Animal Origin ◽  
Prolonged Storage ◽  
Amino Acid Residues ◽  
Ph Optimum ◽  
French Beans ◽  
Purification And Properties ◽  
Endopeptidase Activity

1. A proteolytic enzyme with some features of a carboxypeptidase has been purified some 1180-fold from the sap of French beans (Phaseolus vulgaris var. Prince). A bright blue protein, plastocyanin, was separated from the enzyme by DEAE-cellulose chromatography. 2. Unlike carboxypeptidase A or B of animal origin, there is no evidence that the enzyme is a metalloprotein. There was no stimulation of activity by a number of metal ions, reducing agents or 2-mercapto-ethanol. Neither EDTA nor 1,10-o-phenanthroline inhibited the enzyme. 3. The proteolytic enzyme from beans, readily soluble at neutral or slightly acidic pH values, has a pH optimum of pH5.6 for the hydrolysis of leucine from benzyloxy-carbonylglycyl-l-leucine. Solutions of the enzyme in 0.1m-sodium acetate, pH5.5, lose about 2% of their activity/week at 4 degrees . Virtually no loss of activity results after prolonged storage at -15 degrees . 4. Incubation of the bean enzyme with peptides indicates that the enzyme will release acidic, neutral and basic amino acid residues as well as proline, although adjacent acidic residues in a peptide appear to inhibit the enzyme. The possibility of endopeptidase activity in the purified preparation requires further examination.

The cAMP-dependent kinase pathway does not sensitize the cloned vanilloid receptor type 1 expressed in Xenopus oocytes or Aplysia neurons

2000 ◽  
Vol 288 (1) ◽  
pp. 57-60 ◽  
Author(s):  
Yong-Seok Lee ◽  
Jin-A Lee ◽  
Jooyoung Jung ◽  
Uhtaek Oh ◽  
Bong-Kiun Kaang
Keyword(s):  
Xenopus Oocytes ◽  
Vanilloid Receptor ◽  
Receptor Type ◽  
Aplysia Neurons ◽  
Kinase Pathway

scholarly journals Insulin Granule-Loaded MicroPlates for Modulating Blood Glucose Levels in Type-1 Diabetes

2021 ◽  
Author(s):  
Rosita Primavera ◽  
Elena Bellotti ◽  
Daniele Di Mascolo ◽  
Martina Di Francesco ◽  
Jing Wang ◽  
...  
Keyword(s):  
Type 1 Diabetes ◽  
Blood Glucose ◽  
Glucose Levels ◽  
Blood Glucose Levels ◽  
Insulin Granule

Identification and properties of a neuropeptide-degrading endopeptidase (neprilysin) of Ascaris suum muscle

Parasitology ◽  
1995 ◽  
Vol 111 (5) ◽  
pp. 599-608 ◽  
Author(s):  
M. Sajid ◽  
R. E. Isaac
Keyword(s):  
Metal Ion ◽  
Ascaris Suum ◽  
Significant Proportion ◽  
Neutral Endopeptidase ◽  
Integral Membrane Protein ◽  
Hydrolytic Activity ◽  
The Body ◽  
Ph Optimum ◽  
Muscle Enzyme ◽  
Endopeptidase Activity

SUMMARYWe have previously identified in membranes of the locomotory muscle of Ascaris suum a phosphoramidon-sensitive endopeptidase which hydrolyses the neuropeptide AF1 (Lys-Asn-Glu-Phe-Ile-Arg-Phe-NH2) by cleavage of the Glu3-Phe4 bond (Sajid & Isaac, 1994). We have determined the properties of this neuropeptide-degrading enzyme of A. suum muscle using AKH-I (ρGlu-Leu-Asn-Phe-Thr-Pro-Asn-Trp-Gly-Thr-NH2) and [D-Ala2, Leu5]enkephalin as convenient endopeptidase substrates. Phosphoramidon, thiorphan and SQ 28603, potent inhibitors of mammalian neprilysin (neutral endopeptidase, endopeptidase 24.11), inhibited the endopeptidase activity towards AKH-I with IC50 values of 0·13 μM, 22 μM and 6·3 μM, respectively. Two other neprilysin inhibitors (SCH 32615 and SCH 39370) and the bivalent metal ion chelators, EDTA (1 mM) and 1, 10 bis-phenanthroline (1 mM) failed to inhibit the nematode enzyme. The endopeptidase had a neutral pH optimum and a significant proportion (45%)of the enzyme activity partitioned into the detergent-rich phase of Triton X-114, indicating that the enzyme is an integral membrane protein. The muscle enzyme also attacked [D-Ala2, Leu5]enkephalin cleaving the Gly3-Phe4 bond and this hydrolytic activity was inhibited by phosphoramidon and thiorphan (IC50, 0·28 ρM and 15·8 ρM, respectively) but not by EDTA and 1,10 bis-phenanthroline. The phosphoramidon-sensitive endopeptidase activity was detected on intact muscle cells prepared by collagenase treatment of the body wall musculature, indicating that endopeptidase is accessible to peptide molecules that interact with the cell surface.

HIV-1 Integrase: High-Level Production and Screening Assay for the Endonucleolytic Activity

1992 ◽  
Vol 3 (2) ◽  
pp. 113-119 ◽  
Author(s):  
A. Billich ◽  
M. Schauer ◽  
S. Frank ◽  
B. Rosenwirth ◽  
S. Billich
Keyword(s):  
Deae Cellulose ◽  
Enzyme Concentration ◽  
Screening Assay ◽  
Recombinant Bacteria ◽  
Ph Optimum ◽  
Protein Preparation ◽  
Immunodeficiency Virus ◽  
Inhibitory Potential ◽  
High Level

The integration protein of the human immunodeficiency virus type 1 was purified from recombinant bacteria overproducing this enzyme. The final step of purification, namely chromatography on polyUsepharose, yielded a homogeneous protein preparation showing specific DNA cutting and joining activities. For a convenient assay of the endonuclease reaction, a 21-mer duplex oligonucleotide corresponding to the U5-LTR end of the viral DNA was radiolabeled at the dinucleotide that is removed by the enzyme. After the reaction, assay mixtures were passed through DEAE-cellulose filters which bind the substrate, but not the short radiolabeled product. Thus, an enzyme-dependent decrease of bound radioactivity was observed with time. Reaction rate was linearly dependent on enzyme concentration and the amount of substrate used was far below saturating concentrations. The reaction showed a pH-optimum at 7.5 and was strictly dependent on the presence of Mn2+. The presence of reducing agents like 2-mercaptoethanol was not essential for enzymatic activity. The assay was used to test selected compounds for their inhibitory potential against integrase. Typical inhibitors of DNA-topoisomerases did not inhibit the endonuclease reaction, with the exception of the intercalative agent actinomycin D which blocked the reaction with an IC50-value of 3 μM. Dextran sulphate inhibited the enzyme with an IC50 = 1.6 μg ml−1.

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