Mutations affecting the activity of the cyclodextrin glucanotransferase of Paenibacillus pabuli US132: insights into the low hydrolytic activity of cyclodextrin glucanotransferases

Biologia ◽  
2012 ◽  
Vol 67 (4) ◽  
Author(s):  
Sonia Jemli ◽  
Mamdouh Ben-Ali ◽  
Hajer Ben-Hlima ◽  
Bassem Khemakhem ◽  
Samir Bejar
Keyword(s):  
Hydrolytic Activity ◽  
Influential Factor ◽  
Rational Approach ◽  
Cyclodextrin Glucanotransferase ◽  
Hydrolytic Activities ◽  
Maltogenic Amylase ◽  
Structural Barrier ◽  
First Time

AbstractThe cyclodextrin glucanotransferase from Paenibacillus pabuli US132 (US132 CGTase) was engineered using a rational approach in an attempt to provide it with anti-staling properties comparable to those of the commercial maltogenic amylase (Novamyl). The study aimed to concurrently decrease the cyclization activity and increase the hydrolytic activity of US132 CGTase. A five-residue loop (PAGFS) was inserted, alone or with the substitution of essential residues for cyclization (G180, L194 and Y195), mimicking the case of Novamyl. The findings indicate that, unlike the case of the CGTase of Thermoanerobacterium thermosulfurigenes strain EM1 whose initial high hydrolytic activity was exceptional, these mutations completely abolished the cyclization and hydrolytic activities of the US132 CGTase. This suggests that those mutations are not able to convert conventional CGTases, whose hydrolytic activities are very weak, into hydrolases. Accordingly, and for the first time, a structural barrier at subsite −3 was advanced as an influential factor which might explain the low hydrolytic activity of conventional CGTases.

scholarly journals Increasing the quality of seismic interpretation

2016 ◽  
Vol 4 (3) ◽  
pp. T395-T402 ◽  
Author(s):  
Euan J. Macrae ◽  
Clare E. Bond ◽  
Zoe K. Shipton ◽  
Rebecca J. Lunn
Keyword(s):  
Controlled Trial ◽  
Causal Link ◽  
Environmental Risks ◽  
Influential Factor ◽  
Data Sets ◽  
Seismic Section ◽  
Randomized Controlled ◽  
First Time ◽  
Geologic Data

Geologic models are based on the interpretation of spatially sparse and limited resolution data sets. Nonunique interpretations often exist, resulting in commercial, safety, and environmental risks. We surveyed 444 experienced geoscientists to assess the validity of their interpretations of a seismic section for which multiple concepts honor the data. The most statistically influential factor in improving interpretation was writing about geologic time. A randomized controlled trial identified for the first time a significant causal link between being explicitly requested to describe the temporal geologic evolution of an interpretation and increased interpretation quality. These results have important implications for interpreting geologic data and communicating uncertainty in models.

scholarly journals Updated pseudoscalar contributions to the hadronic light-by-light of the muon (g − 2)

2016 ◽  
Vol 31 (31) ◽  
pp. 1630034 ◽  
Author(s):  
Pablo Sanchez-Puertas ◽  
Pere Masjuan
Keyword(s):  
Systematic Uncertainty ◽  
Form Factors ◽  
Data Driven ◽  
Rational Approach ◽  
Transition Form ◽  
Pole Contribution ◽  
Model Independent ◽  
First Time

In this work, we present our recent results on a new and alternative data-driven determination for the hadronic light-by-light pseudoscalar pole contribution to the muon (g − 2). Our approach is based on Canterbury approximants, a rational approach to describe the required transition form factors, which provides a systematic and model-independent framework beyond traditional large-[Formula: see text] approaches. As a result, we obtain a competitive determination with errors according to future (g − 2) experiments including, for the first time, a well-defined systematic uncertainty.

State of Weathering: The Search for a Rational Approach

1986 ◽  
Vol 2 (1) ◽  
pp. 193-198
Author(s):  
W. R. Dearman
Keyword(s):  
Hong Kong ◽  
Rock Mass ◽  
Rock Material ◽  
Engineering Properties ◽  
Rational Approach ◽  
Drill Core ◽  
Definition Of ◽  
First Time ◽  
Weathering Grades ◽  
Simple Definition

AbstractIn BS 5930:1981 both the state of weathering of rock material and a scale of weathering grades for the rock mass are included in a Code for the first time. The schemes proposed are largely derivative from those proposed by Working Parties of the Engineering Group, which in turn benefited from earlier studies in Hong Kong and Australia.The descriptive terms used for rock material: fresh, discoloured, decomposed, disintegrated, are defined, and the stages of weathering subdivided using qualifying terms, for example 'partially discoloured'. These descriptive qualifying terms may be quantified if necessary, but no indication is given as to how this should be done.Following recent Australian practice, the scale of weathering grades of the rock mass is described in the terms applied to the rock material. Except in the case of Grade 1, Fresh, discontinuities and other defects of the rock mass are not mentioned. This implies, and it needs emphasizing, that the descriptive terms for the degree of weathering should provide a reliable indication of the effects of weathering on the engineering properties or engineering behaviour of the rock mass. The material and the defects, such as discontinuities in the rock mass, therefore need to be described separately.A descriptive scheme is proposed for the simple definition of weathering classes of rock material, and application of these classes to the description of the rock mass is also considered.The effect of scale, particularly the spacing of discontinuities and thickness of highly weathered zones, is important in assessing the engineering properties of the rock mass. This can be dealt with effectively in the descriptive logging of drill core and rock exposures.

scholarly journals Removal of lead from aqueous solutions using three biosorbents of aquatic origin with the emphasis on the affective factors

2022 ◽  
Vol 12 (1) ◽  
Author(s):  
Maryam Rezaei ◽  
Nima Pourang ◽  
Ali Mashinchian Moradi
Keyword(s):  
Aqueous Solutions ◽  
Langmuir Model ◽  
Influential Factor ◽  
Freundlich Model ◽  
Box Behnken Design ◽  
Initial Concentration ◽  
Affective Factors ◽  
Maximum Sorption ◽  
First Time ◽  
Xrf Analyses

AbstractThe biosorptive potentials of three aquatics-based biosorbents, including shells of a bivalve mollusk and scales of two fish species for Pb removal from aqueous solutions were evaluated, for the first time. A Box–Behnken design with the response surface methodology was used to investigate the effects of the seven important variables (contact time, temperature, initial concentration, dosage, size, salinity and pH) on the sorption capacity of the sorbents. Among the seven studied factors, the effects of biosorbent dosage, initial concentration and pH were significant for all the response variables, while biosorbent size was not significant for any of the responses. The initial concentration was the most influential factor. The presence of Pb ions on the surfaces of the biosorbents after the adsorption was clearly confirmed by the SEM–EDX and XRF analyses. The maximum sorption capacities of the biosorbents were comparable to the literature and the descending order was as follows: scales of Rutilus kutum and Oncorhynchus mykiss and the shells of Cerastoderma glaucum. The isotherm studies revealed Langmuir model applicability for the Pb adsorption by R. kutum and O. mykiss scales, while Freundlich model was fitted to the adsorption C. glaucum shells.

scholarly journals Investigating Enzyme Activity of Immobilized Candida rugosa Lipase

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Bhagya Sri Kaja ◽  
Stephen Lumor ◽  
Samuel Besong ◽  
Bettina Taylor ◽  
Gulnihal Ozbay
Keyword(s):  
Milk Fat ◽  
Candida Rugosa ◽  
Catalytic Efficiency ◽  
Hydrolytic Activity ◽  
Candida Rugosa Lipase ◽  
Support Materials ◽  
Fatty Acid Chain ◽  
Hydrolytic Activities ◽  
Immobilized Candida Rugosa Lipase ◽  
Immobilization Techniques

Candida rugosa lipase is a food-grade enzyme that is extensively utilized in the dairy processing industry for milk fat hydrolysis. The enzyme is mainly employed to modify the fatty acid chain length that results in the enhancement of flavors. The hydrolytic activities of C. rugosa lipase (fungal source) in its free and immobilized forms were investigated at different pH and temperature settings. The main objective of this study was to understand how different support materials (Celite-545, Sephadex G-25, and chitosan) and immobilization techniques alter lipase activity and stability. Our results indicated that hydrolytic activity increased significantly with immobilization on Celite-545. In general, immobilization resulted in considerable improvements in the stability of the enzyme with variations in pH and temperature. Immobilization on Celite-545 led to the highest catalytic efficiency. Remarkable improvements in the recovery and reusability of the immobilized lipases were noted. Comparatively, the acetone immobilization procedure resulted in higher activities than alcohol immobilization. In conclusion, the activity of C. rugosa lipase was enhanced most significantly when immobilized on Celite-545 using acetone as an adsorption solvent.

scholarly journals Alteration of Leucine Aminopeptidase from Streptomyces septatus TH-2 to Phenylalanine Aminopeptidase by Site-Directed Mutagenesis

2005 ◽  
Vol 71 (11) ◽  
pp. 7229-7235 ◽  
Author(s):  
Jiro Arima ◽  
Yoshiko Uesugi ◽  
Masaki Iwabuchi ◽  
Tadashi Hatanaka
Keyword(s):  
Methyl Ester ◽  
Leucine Aminopeptidase ◽  
Hydrolytic Activity ◽  
Site Directed Mutagenesis ◽  
Saturation Mutagenesis ◽  
Side Chain ◽  
Directed Mutagenesis ◽  
Wild Type ◽  
Peptide Substrates ◽  
Hydrolytic Activities

ABSTRACT To tailor leucine aminopeptidase from Streptomyces septatus TH-2 (SSAP) to become a convenient biocatalyst, we are interested in Phe221 of SSAP, which is thought to interact with the side chain of the N-terminal residue of the substrate. By using saturation mutagenesis, the feasibility of altering the performance of SSAP was evaluated. The hydrolytic activities of 19 mutants were investigated using aminoacyl p-nitroanilide (pNA) derivatives as substrates. Replacement of Phe221 resulted in changes in the activities of all the mutants. Three of these mutants, F221G, F221A, and F221S, specifically hydrolyzed l-Phe-pNA, and F221I SSAP exhibited hydrolytic activity with l-Leu-pNA exceeding that of the wild type. Although the hydrolytic activities with peptide substrates decreased, the hydrolytic activities with amide and methyl ester substrates were proportional to the changes in the hydrolytic activities with pNA derivatives. Furthermore, based on a comparative kinetic study, the mechanism underlying the alteration in the preference of SSAP from leucine to phenylalanine is discussed.

scholarly journals The identification of distinctive forms of human α2-macroglobulin by using the numerical relationship between trypsin binding in α- and β-modes

1979 ◽  
Vol 177 (2) ◽  
pp. 501-508 ◽  
Author(s):  
R M Topping ◽  
A H Craven
Keyword(s):  
Bound States ◽  
Proteinase Inhibitors ◽  
Serine Proteinase ◽  
Preceding Paper ◽  
Hydrolytic Activity ◽  
Clinical Value ◽  
Straight Line ◽  
Hydrolytic Activities ◽  
Linear Differential ◽  
Alpha 1 Antitrypsin

Interactions between the serine proteinase trypsin and the protein proteinase inhibitors in human blood were expressed in terms of a coupled set of non-linear differential equations, which has been solved for each of 110 samples of serum obtained from colleagues and from a variety of hospital sources. Optimization of nine unknown theoretical parameters and 21 experimental rate measurements of the hydrolytic activity of trypsin in free and bound states after admixture with various amounts of a given serum was achieved by an iterative procedure using initial estimates of the parameters derived from the “four-straight-line” model described in the preceding paper [Topping & Seilman (1979) Biochem. J. 177, 493–499.] Such a procedure yielded the following information for each sample of serum examined: (a) the concentrations of alpha 1-antitrypsin and alpha 2-macroglobulin; (b) the unequivocal assignment of alpha 2-macroglobulin into one of seven categories on the basis of trypsin binding in two kinetically differentiated modes (alpha and beta); (c) the hydrolytic activities of trypsin (versus Bz-Arg-OEt) when bound to alpha 1-antitrypsin, and to alpha 2-macroglobulin in the alpha- and beta-modes. Molecular interpretations of the binding of trypsin to alpha 2-macroglobulin are discussed and the potential clinical value of recognizing the nature of such binding is reported.

Synergistic action of cyclodextrin glucanotransferase and maltogenic amylase improves the bioconversion of starch to malto-oligosaccharides

2021 ◽  
Vol 103 ◽  
pp. 9-17
Author(s):  
Nardiah Rizwana Jaafar ◽  
Rabi’atul Adawiyah Ahmad ◽  
Noor Namirah Nawawi ◽  
Noor Hidayah Abd Rahman ◽  
Nur Arbainah Shamsul Annuar ◽  
...  
Keyword(s):  
Synergistic Action ◽  
Cyclodextrin Glucanotransferase ◽  
Maltogenic Amylase

scholarly journals Pectin Solubilization and Enzymic Activity of Tomato Fruit Locule Tissue Cell Wall

HortScience ◽  
1996 ◽  
Vol 31 (4) ◽  
pp. 599d-599
Author(s):  
Guiwen W. Cheng ◽  
Donald J. Huber
Keyword(s):  
Main Chain ◽  
Tomato Fruit ◽  
Hydrolytic Activity ◽  
Enzymic Activity ◽  
Tissue Cell ◽  
Uronic Acids ◽  
Hydrolytic Activities ◽  
Neutral Sugars ◽  
Acid Release ◽  
Locule Tissue

Hydrolytic activities in liquefying locule tissue of mature-green tomato (Lycopersicon esculentum Mill. `Solar Set') fruit were studied in pursuing the understanding of mechanisms involved in the rheological changes occurring in this tissue. Ethanol-insoluble solids (EIS) were prepared with and without enzyme-inactivating treatment. The release of uronic acids from enzymically active EIS incubated under autolysic conditions was 5-fold higher than recoveries from inactive EIS. Uronic acid release was partially inhibited by 1 mm Hg2+. Cell-free proteins extracts from active EIS exhibited hydrolytic activity against inactive EIS. Pectins released from active EIS showed no evidence of main-chain hydrolysis. Neutral sugars recovered as 80% ethanol-soluble products of autolytic reactions included glc, gal, rha, ara, xyl, and man. Gal was recovered at significant higher levels in autolysates of active EIS. Glycosidases present at high activities in locule tissue included α- and β-galactosidases, β-mannosidase, β-arabinosidase, and β-glucosidase. The results confirm our earlier findings that the metabolism of water, chelator, and alkali-soluble pectins in tomato locule tissue involves deglycosylation with no apparent depolymeriation. These changes alone appear to be inadequate in explaining the unique rheological characteristics in locule gel tissue.

Increasing Hydrolytic Activity of Lipase on Palm Oil by PCR-Based Random Mutagenesis

2020 ◽  
Vol 3 (3) ◽  
pp. 78-87
Author(s):  
Maria Dita Febriani Lumban Gaol ◽  
Andreas Adhi Satya ◽  
Esti Puspitasari ◽  
Nisa Rachmania Mubarik ◽  
Antonius Suwanto
Keyword(s):  
Palm Oil ◽  
Active Site ◽  
Random Mutagenesis ◽  
Hydrolytic Activity ◽  
Optimum Temperature ◽  
Active Site Residue ◽  
Protein Modelling ◽  
High Preference ◽  
Hydrolytic Activities ◽  
Increased Activity

ABSTRACT Random mutagenesis technique is a powerful technique capable of producing enzymes with desired biocatalytic activity. This study aims to obtain a mutant lipase with improved hydrolytic activity on palm oil substrate using random mutagenesis technique. Random mutagenesis by error-prone PCR was used to generate mutant lipases. A total of 1101 mutants were obtained, out of which two mutants, Lip M14.25, and Lip M14.57, showed an increased relative hydrolytic activity. Lip M14.25 and Lip M14.57 demonstrated a 14% and 16% increased activity respectively. A comparison of the mutants' hydrolytic activities using p-nitrophenyl esters showed a significantly high preference for p-nitrophenyl palmitate. Furthermore, the mutant,  Lip M14.25 showed its highest activity at pH 5, and Lip M14.57 exhibited a 10 oC decrease in optimum temperature. The two mutants' protein modelling showed the substitution of N44S/S202N on M14.25 and F154L/S265C on M14.57 lipase, which caused changes in conformation and active site residue distance of the lipase. The study found two mutants of lipase, M14.25 and M14.57, which showed improved hydrolytic activity on palm oil substrate.

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