Effect of oxidation of methionine in a peptide substrate for human elastases: A model for inactivation of α1-protease inhibitor

Mar, Eric G. Del; Brodrick, James W.; Geokas, Michael C.; Largman, Corey

doi:10.1016/0006-291x(79)92054-0

Cited by 22 publications

(9 citation statements)

References 11 publications

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“…Specific protease enzyme activity of SeCHY was determined using a synthetic peptide substrate SAAPFpNA (N-succinyl-alanine-alanine-proline-phenylalanine- p -nitroanilide) according to published method [ 22 ]. Briefly, 5 μL of 1 mM substrate was added to 10 μL enzyme extract.…”

Section: Methodsmentioning

confidence: 99%

Optimization of recombinant bacteria expressing dsRNA to enhance insecticidal activity against a lepidopteran insect, Spodoptera exigua

Vatanparast

Kim

2017

PLoS ONE

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Double-stranded RNA (dsRNA) has been applied to control insect pests due to its induction of RNA interference (RNAi) of a specific target gene expression. However, developing dsRNA-based insecticidal agent has been a great challenge especially against lepidopteran insect pests due to variations in RNAi efficiency. The objective of this study was to screen genes of chymotrypsins (SeCHYs) essential for the survival of the beet armyworm, Spodoptera exigua, to construct insecticidal dsRNA. In addition, an optimal oral delivery method was developed using recombinant bacteria. At least 7 SeCHY genes were predicted from S. exigua transcriptomes. Subsequent analyses indicated that SeCHY2 was widely expressed in different developmental stages and larval tissues by RT-PCR and its expression knockdown by RNAi caused high mortality along with immunosuppression. However, a large amount of dsRNA was required to efficiently kill late instars of S. exigua because of high RNase activity in their midgut lumen. To minimize dsRNA degradation, bacterial expression and formulation of dsRNA were performed in HT115 Escherichia coli using L4440 expression vector. dsRNA (300 bp) specific to SeCHY2 overexpressed in E. coli was toxic to S. exigua larvae after oral administration. To enhance dsRNA release from E. coli, bacterial cells were sonicated before oral administration. RNAi efficiency of sonicated bacteria was significantly increased, causing higher larval mortality at oral administration. Moreover, targeting young larvae possessing weak RNase activity in the midgut lumen significantly enhanced RNAi efficiency and subsequent insecticidal activity against S. exigua.

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Section: Methodsmentioning

confidence: 99%

Optimization of recombinant bacteria expressing dsRNA to enhance insecticidal activity against a lepidopteran insect, Spodoptera exigua

Vatanparast

Kim

2017

PLoS ONE

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“…One unit of trypsin activity was defi ned as the amount of enzyme required to release 1 μmol 4-nitroaniline · min -1 . Chymotrypsin activity was determined (Del Mar et al 1979), with slight modifications, as described for trypsin, but using SAPNA (#S7388, Sigma-Aldrich) as the substrate in DMSO and 60 mmol Tris-HCl, pH 8 and CaCl 2 , pH 8. For controls, the crude extract was inactivated (water bath at 95°C for 5 min).…”

Section: Methodsmentioning

confidence: 99%

Circadian cycle of digestive enzyme production at fasting and feeding conditions in Nile tilapia, Oreochromis niloticus (Actinopterygii: Perciformes: Cichlidae)

Montoya-Mejía

Rodríguez‐González

Nolasco-Soria

2016

Acta Ichthyol. Piscat.

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“…Then, 20 μL of the enzymatic extracts was added to 980 μL of the substrate solution and, after incubation at 25°C, the absorbance at 410 nm was recorded [18]. Chymotrypsin activity was expressed as U/mg.…”

Section: Methodsmentioning

confidence: 99%

A new chymotrypsin-like serine protease involved in dietary protein digestion in a primitive animal, Scorpio maurus: purification and biochemical characterization

et al. 2011

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BackgroundMost recent works on chymotrypsins have been focused on marine animals and insects. However, no study was reported in chelicerate.ResultsScorpion chymotrypsin-like protease (SCP) was purified to homogeneity from delipidated hepatopancreases. The protease NH2-terminal sequence exhibited more than 60% monoacids identity with those of insect putative peptidases. The protease displayed no sequence homology with classical proteases. From this point of view, the protease recalls the case of the scorpion lipase which displayed no sequence homology with known lipases. The scorpion amylase purified and characterized by our time, has an amino-acids sequence similar to those of mammalian amylases. The enzyme was characterized with respect its biochemical properties: it was active on a chymotrypsin substrate and had an apparent molecular mass of 25 kDa, like the classically known chymotrypsins. The dependence of the SCP activity and stability on pH and temperature was similar to that of mammalian chymotrypsin proteases. However, the SCP displayed a lower specific activity and a boarder pH activity range (from 6 to 9).Conclusionlower animal have a less evaluated digestive organ: a hepatopancreas, whereas, higher ones possess individualized pancreas and liver. A new chymotrypsin-like protease was purified for the first time from the scorpion hepatopancreas. Its biochemical characterization showed new features as compared to classical chymotrypsin-higher-animals proteases.

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Effect of oxidation of methionine in a peptide substrate for human elastases: A model for inactivation of α1-protease inhibitor

Cited by 22 publications

References 11 publications

Optimization of recombinant bacteria expressing dsRNA to enhance insecticidal activity against a lepidopteran insect, Spodoptera exigua

Optimization of recombinant bacteria expressing dsRNA to enhance insecticidal activity against a lepidopteran insect, Spodoptera exigua

Circadian cycle of digestive enzyme production at fasting and feeding conditions in Nile tilapia, Oreochromis niloticus (Actinopterygii: Perciformes: Cichlidae)

A new chymotrypsin-like serine protease involved in dietary protein digestion in a primitive animal, Scorpio maurus: purification and biochemical characterization

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