Identification and partial characterization of digestive proteinases from two species of bedbug (Hemiptera: Cimicidae)

1982 ◽  
Vol 60 (8) ◽  
pp. 1837-1840 ◽  
Author(s):  
Jon G. Houseman ◽  
A. E. R. Downe
Keyword(s):  
Cathepsin B ◽  
Horse Serum ◽  
Cimex Lectularius ◽  
Aminopeptidase Activity ◽  
Blood Sucking ◽  
Digestive Proteinases ◽  
Cimex Hemipterus ◽  
Hydrolysis Of ◽  
Optimal Ph

The digestive midgut of Cimex hemipterus (Fabr.) and Cimex lectularius L. contains cathepsin B, aminopeptidase, and an acidic proteinase that hydrolyzes haemoglobin at an optimal pH of 3.4. Cathepsin B was demonstrated by hydrolysis of benzoyl-DL-arginine-β-napthylamine at an optimal pH of 5.4. Hydrolysis of the substrate was activated by thiol chemicals and EDTA and inhibited by iodoacetamide (IAA) and horse serum. Maximum aminopeptidasehydrolysis of leucine-p-nitroanilide occurred at pH 8.4. Aminopeptidase activity was activated by MgCl2 and inhibited by EDTA, thiol chemicals, and CaCl2. Only C. hemipterus aminopeptidase was inhibited by IAA. The digestive proteinases in bedbugs are similar to those reported for other blood-sucking hemipteran insects.

Cathepsin B and aminopeptidase in the posterior midgut of Phymata wolffii Stål (Hemiptera: Phymatidae)

1985 ◽  
Vol 63 (6) ◽  
pp. 1288-1291 ◽  
Author(s):  
Jon G. Houseman ◽  
P. E. Morrison ◽  
A. E. R. Downe
Keyword(s):  
Molecular Weight ◽  
Trypsin Inhibitor ◽  
Cathepsin B ◽  
Ethylenediaminetetraacetic Acid ◽  
Soybean Trypsin Inhibitor ◽  
Aminopeptidase Activity ◽  
Chloromethyl Ketone ◽  
Posterior Midgut ◽  
Hydrolysis Of

The posterior midgut of the phymatid Phymata wolffii Stål contains cathepsin B and aminopeptidase activity. Identification of cathepsin B was based on maximal hydrolysis of benzoyl-DL-arginine-2-naphthylamide and benzoyl-DL-arginine-p-nitroanilide at pH 5.8 and 5.5, respectively. Cathepsin B hydrolysis of the tested substrates was activated by thiol chemicals and ethylenediaminetetraacetic acid (EDTA) and inhibited by tosyl-L-lysine chloromethyl ketone, iodoacetamide, and soybean trypsin inhibitor. Aminopeptidase hydrolyzed leucine-p-nitroanilide maximally at pH 7.8 and hydrolysis of the substrate was activated by magnesium and inhibited by EDTA, dithiothreitol, glutathione, and cysteine. The molecular weight of cathepsin B was 40 000 and was greater than 150 000 for aminopeptidase.

Characterization of lactococci and lactobacilli isolated from semihard goats' cheese

1991 ◽  
Vol 58 (1) ◽  
pp. 137-145 ◽  
Author(s):  
Teresa Requena ◽  
Carmen Peláez ◽  
Michel J. Desmazeaud
Keyword(s):  
Leucine Aminopeptidase ◽  
Sodium Dodecyl ◽  
Skim Milk ◽  
Titratable Acidity ◽  
Aminopeptidase Activity ◽  
Whole Cells ◽  
Alanine Aminopeptidase ◽  
Triton X ◽  
Hydrolysis Of

SummarySeveral strains ofLactococcus lactissubsp.lactis, Lactobacillus caseiandLactobacillus plantarumisolated from traditional goats' cheese have been studied for titratable acidity, proteolysis in milk and enzymic activities. Aminopeptidasc activities were measured with whole cells and cells permeabilized with Triton X-100. Caseinolytic activity was investigated using electrophoresis in polyacrylamide gel with sodium dodecyl sulphate.Lc. lactissubsp.lactishad a level of proteolytic activity in skim milk greater than that ofLb. casei, while this activity inLb. plantarumwas very low. Alanine aminopeptidase activity was almost non-existent for all strains tested, while lysine aminopeptidase activity appeared to be of fundamentally intracellular origin. Leucine aminopeptidase activity was also greater in cells that had been permeabilized than in whole cells forLb. caseiandLb. plantarum. Lc. lactissubsp.lactisleucine aminopeptidase activity was greater in whole cells. No significant hydrolysis of casein was found withLb. caseiI FPL 725 andLb. plantarumIFPL 722 permeabilized with Triton X-100 after 24 h incubation with whole bovine casein.

scholarly journals Purification and characterization of a new endoglucanase from Clostridium thermocellum

1992 ◽  
Vol 283 (1) ◽  
pp. 69-73 ◽  
Author(s):  
M P M Romaniec ◽  
U Fauth ◽  
T Kobayashi ◽  
N S Huskisson ◽  
P J Barker ◽  
...  
Keyword(s):  
Clostridium Thermocellum ◽  
Reducing Sugars ◽  
Rapid Decrease ◽  
Purification And Characterization ◽  
Temperature Optimum ◽  
Apparent Homogeneity ◽  
Sds Page ◽  
Hydrolysis Of ◽  
Optimal Ph

An endoglucanase (1,4-beta-D-glucan glucanohydrolase, EC 3.2.1.4) from the thermophilic anaerobe Clostridium thermocellum was purified to apparent homogeneity without the use of denaturants. No carbohydrate is associated with the endoglucanase. A molecular mass of 76,000 Da was determined by SDS/PAGE. The optimal pH is 7.0 and the enzyme is isoelectric at pH 5.05. The enzyme has a temperature optimum of 70 degrees C and retains approx. 50% of its activity after 48 h at 60 degrees C. Hydrolysis of CM-cellulose takes place with a rapid decrease in viscosity but a slow liberation of reducing sugars, indicating an endoglucanase type of activity. The endoglucanase shows little ability to hydrolyse highly ordered cellulose. Cellobiose inhibits whereas Mg2+ and Ca2+ stimulate the activity. The enzyme is completely inactivated by 1 mM-Hg2+ and is inhibited by a thiol-blocking reagent.

scholarly journals Characterization of a Zn2+-requiring glycerophosphocholine cholinephosphodiesterase possessing p-nitrophenylphosphocholine phosphodiesterase activity

1992 ◽  
Vol 286 (2) ◽  
pp. 435-440 ◽  
Author(s):  
D E Sok ◽  
M R Kim
Keyword(s):  
Bacillus Cereus ◽  
Molecular Mass ◽  
Mouse Brain ◽  
Concanavalin A ◽  
Heat Denaturation ◽  
Phosphodiesterase Activity ◽  
Optimum Ph ◽  
Hydrolysis Of ◽  
Optimal Ph

p-Nitrophenylphosphocholine phosphodiesterase activity was purified 5000-fold from mouse brain by treatment of membranes with Bacillus cereus phospholipase C preparation and sequential chromatographies on concanavalin A-Sepharose and CM-Sephadex columns. The phosphodiesterase (Zn(2+)-requiring) showed Km and Vmax. values of 5.5 microM and 4.2 mumol/min per mg respectively in the hydrolysis of p-nitrophenylphosphocholine, and possessed an optimum pH of 10.5 and a molecular mass of approx. 74 kDa. The purified enzyme was found to convert glycerophosphocholine into glycerol and phosphocholine, with Km and Vmax. of 48 microM and 5 mumol/min per mg respectively. In the hydrolysis of glycerophosphocholine the enzyme also exhibited a Zn2+ requirement and optimal pH at 10.5. Additionally, the p-nitrophenylphosphocholine phosphodiesterase activity was competitively inhibited by glycerophosphocholine, with a Ki value of 50 microM. These observations, together with chromatographic behaviour and heat-denaturation analyses, indicate that both p-nitrophenylphosphocholine phosphodiesterase and glycerophosphocholine cholinephosphodiesterase activities reside in the same protein.

CATHEPSIN B AND AMINOPEPTIDASE ACTIVITY IN THE POSTERIOR MIDGUT OF EUSCHISTUS EUSCHISTOIDES (HEMIPTERA: PENTATOMIDAE)

1984 ◽  
Vol 116 (10) ◽  
pp. 1393-1396 ◽  
Author(s):  
Jon G. Houseman ◽  
W. K. MacNaughton ◽  
A. E. R. Downe
Keyword(s):  
Cathepsin B ◽  
Blood Feeding ◽  
Aminopeptidase Activity ◽  
Posterior Midgut ◽  
Hydrolysis Of

AbstractThe posterior midgut of a seed-feeding pentatomid, Euschistus euschistoides (Vollenhoven), contains the proteinases cathepsin B and aminopeptidase. Cadiepsin B hydrolysis of benzoyl-DL-arginine-2-naphthylamide is activated by thiol chemicals and EDTA. Aminopeptidase hydrolysis of leucine-p-nitroanilide is activated by MgCl2 and inhibited by cysteine, glutathione, EDTA, and CaCl2. These results are similar to those obtained for cathepsin B and aminopeptidase from blood-feeding Hemiptera and support the hypothesis that catheptic proteinases are unique to this order.

scholarly journals Characterization of bacterial communities associated with blood-fed and starved tropical bed bugs, Cimex hemipterus (F.) (Hemiptera): a high throughput metabarcoding analysis

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Li Lim ◽  
Abdul Hafiz Ab Majid
Keyword(s):  
Microbial Community ◽  
Bacterial Communities ◽  
Hypervariable Region ◽  
Cimex Lectularius ◽  
Rrna Gene ◽  
Bed Bugs ◽  
Cimex Hemipterus ◽  
The 16S Rrna Gene ◽  
Bacteria Communities

AbstractWith the development of new metagenomic techniques, the microbial community structure of common bed bugs, Cimex lectularius, is well-studied, while information regarding the constituents of the bacterial communities associated with tropical bed bugs, Cimex hemipterus, is lacking. In this study, the bacteria communities in the blood-fed and starved tropical bed bugs were analysed and characterized by amplifying the v3-v4 hypervariable region of the 16S rRNA gene region, followed by MiSeq Illumina sequencing. Across all samples, Proteobacteria made up more than 99% of the microbial community. An alpha-proteobacterium Wolbachia and gamma-proteobacterium, including Dickeya chrysanthemi and Pseudomonas, were the dominant OTUs at the genus level. Although the dominant OTUs of bacterial communities of blood-fed and starved bed bugs were the same, bacterial genera present in lower numbers were varied. The bacteria load in starved bed bugs was also higher than blood-fed bed bugs.

A preliminary characterization of alkaline digestive proteases in the posterior midgut of the face fly, Musca autumnalis De Geer

1987 ◽  
Vol 65 (3) ◽  
pp. 635-639 ◽  
Author(s):  
F. C. Campbell ◽  
Jon G. Houseman ◽  
P. E. Morrison
Keyword(s):  
Aminopeptidase Activity ◽  
Tetraacetic Acid ◽  
Carboxypeptidase A ◽  
Phenyllactic Acid ◽  
Carboxypeptidase B ◽  
Posterior Midgut ◽  
The Face ◽  
Musca Autumnalis ◽  
Hydrolysis Of

Alkaline proteases in the posterior midgut of the face fly, Musca autumnalis De Geer, were identified using specific synthetic substrates and nonspecific substrate azocasein. Identification was confirmed with potential protease activators and inhibitors. Optimal azocasein hydrolysis occurred at pH 8.0 and substrate hydrolysis was inhibited by EGTA (ethyleneglycol-bis-(2-aminoethyl ether)-N,N-tetraacetic acid), tosyl-L-lysine chloromethyl ketone (TLCK), and soybean trypsin inhibitor (STI). Tryptic proteolysis was identified by maximal hydrolysis, at pH 8.0, of trypsin specific substrates BAPNA (benzoyl-DL-arginine-p-nitroanilide) and TAME (tosyl-L-arginine methyl ester). TAME hydrolysis was inhibited by PMSF (phenylmethylsulfonyl fluoride), STI, pepstatin A, and dithiothreitol (DTT), but BAPNA hydrolysis was inhibited only by STI and DTT. Chymotrypsin was demonstrated by maximal hydrolysis of BTEE (benzoyl-L-tyrosine ethyl ester) at pH 8.0 and DTT, PMSF, and STI inhibited hydrolysis of this substrate. Aminopeptidase activity was demonstrated by maximal hydrolysis of leucine-p-nitro-anilide at pH 8.0 and the peptidase was inhibited by o-phenanthroline. Carboxypeptidase A-like enzyme hydrolyzed hippuryl-DL-phenyllactic acid maximally at pH 7.5 and carboxypeptidase B showed maximum hydrolysis of hippuryl-L-arginine at pH 7.0. Both carboxypeptidases were inhibited by EDTA (ethylene diamine tetraacetic acid), EGTA, and DTT and carboxypeptidase A was also inhibited by PMSF.

scholarly journals Identification and characterization of aminopeptidases from Aplysia californica

1992 ◽  
Vol 286 (3) ◽  
pp. 967-975 ◽  
Author(s):  
W Bawab ◽  
E Querido ◽  
P Crine ◽  
L DesGroseillers
Keyword(s):  
Enzyme Inhibitor ◽  
Aplysia Californica ◽  
Chelating Agent ◽  
Neutral Endopeptidase ◽  
Aminopeptidase Activity ◽  
Bivalent Cation ◽  
Enzyme Preparations ◽  
Membrane Bound ◽  
Hydrolysis Of

Aminopeptidase activities were identified in extracts of kidney, ovotestis, head ganglia, heart and haemolymph of Aplysia californica. These enzyme preparations hydrolysed [3H][Leu]enkephalin at the Try-1-Gly-2 bond as determined by h.p.l.c. analysis of cleavage products. In all these tissues, enkephalin-degrading aminopeptidase activities were present both in membrane-bound and cytosolic fractions. The bivalent-cation-chelating agent, 1,10-phenanthroline, inhibited kidney membrane aminopeptidase activity with an IC50 of 30 microM, suggesting that this enzyme is a metalloproteinase. The aminopeptidase inhibitor amastatin was the most potent inhibitor of [Leu]enkephalin degradation (IC50 25 nM) by membrane-bound aminopeptidase, and bacitracin, bestatin and puromycin were about 100-1000 times less potent. In contrast with membrane-bound aminopeptidase, the cytosolic form is sensitive to puromycin. Angiotensin-converting enzyme inhibitor had no effect on [Leu]enkephalin degradation by kidney membranes, while the neutral endopeptidase inhibitors were poor inhibitors of the enzymes in this preparation. The Km values of the aminopeptidase in the kidney membranes and cytosolic fractions for the [Leu]enkephalin substrate were 2.4 and 7.4 microM respectively. The aminopeptidase present in the kidney membranes also hydrolysed endogenous Phe-Met-Arg-Phe-amide peptide at the Phe-1-Met-2 bond as well as synthetic alanine p-nitroanilide and leucine p-nitroanilide. When used in a competition assay, these substrates inhibited hydrolysis of [3H][Leu]enkephalin, suggesting that the same enzyme degraded all these substrates. Taken together, these results suggest that Aplysia tissues contain both a membrane-bound aminopeptidase related to the mammalian aminopeptidase N and a cytosolic puromycin-sensitive aminopeptidase.

Quantification of small-scale heterogeneity in aquatic aminopeptidase activity

2020 ◽  
Vol 84 ◽  
pp. 127-140
Author(s):  
BM Gaas ◽  
JW Ammerman
Keyword(s):  
Chlorophyll Fluorescence ◽  
Leucine Aminopeptidase ◽  
Hudson River ◽  
Aminopeptidase Activity ◽  
Small Scale ◽  
Analysis Instrument ◽  
Sequential Samples ◽  
Degree Of Confidence ◽  
The Mean ◽  
Hydrolysis Of

Leucine aminopeptidase (LAP) is one of the enzymes involved in the hydrolysis of peptides, and is sometimes used to indicate potential nitrogen limitation in microbes. Small-scale variability has the potential to confound interpretation of underlying patterns in LAP activity in time or space. An automated flow-injection analysis instrument was used to address the small-scale variability of LAP activity within contiguous regions of the Hudson River plume (New Jersey, USA). LAP activity had a coefficient of variation (CV) of ca. 0.5 with occasional values above 1.0. The mean CVs for other biological parameters—chlorophyll fluorescence and nitrate concentration—were similar, and were much lower for salinity. LAP activity changed by an average of 35 nmol l-1 h-1 at different salinities, and variations in LAP activity were higher crossing region boundaries than within a region. Differences in LAP activity were ±100 nmol l-1 h-1 between sequential samples spaced <10 m apart. Variogram analysis indicated an inherent spatial variability of 52 nmol l-1 h-1 throughout the study area. Large changes in LAP activity were often associated with small changes in salinity and chlorophyll fluorescence, and were sensitive to the sampling frequency. This study concludes that LAP measurements in a sample could realistically be expected to range from zero to twice the average, and changes between areas or times should be at least 2-fold to have some degree of confidence that apparent patterns (or lack thereof) in activity are real.

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