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Potential activity of hydrolytic microbial extracellular enzymes were determined in a sandy beach in Sopot, (Southern Baltic Sea) in July 2001. Among of the five monitored enzymes, the highest level of activity (314.28 nM MCA g⁻¹d.w. h⁻¹) was determined in the aminopeptidase whereas chitinase had the lowest level (0.50 nM MUF g⁻¹d.w. h⁻¹) of potential activity. Usually, the ranking of the activity rates of the assayed enzymes was following: aminopeptidase > lipase > β-glucosidase > α-glucosidase > chitinase. Clear gradients in the level of enzymatic activity were determined in horizontal profile of the beach. The maximum activity of studied enzymes was recorded in sand collected under seawater and at the waterline.
Serine proteinases and their natural protein inhibitors belong to the most intensively studied models of protein-protein recognition. Protein inhibitors do not form a single group but can be divided into about 20 different families. Global structures of proteins representing different inhibitor families are completely different and comprise α-helical proteins, β-sheet proteins,α/β-proteins and different folds of small disulfide-rich proteins. Three different types of inhibitors can be distinguished: canonical (standard mechanism) inhibitors, non-canonical inhibitors, and serpins. The canonical inhibitor binds to the enzyme through the exposed and convex binding loop, which is complementary to the active site of the enzyme. The mechanism of inhibition in this group is consistently very similar and resembles that of an ideal substrate. Non-canonical inhibitors, originating from blood sucking organisms, specifically block enzymes of the blood clotting cascade. The interaction is mediated through inhibitor N-terminus which binds to the proteinase forming a parallel β-sheet. There are also extensive secondary interactions which provide an additional buried area and contribute significantly to the strength and specificity of recognition. Serpins are major proteinase inhibitors occurring in plasma. Similarly to canonical inhibitors, serpins interact with their target proteinases in a substrate-like manner. However, in the case of serpins, cleavage of a single peptide bond in a flexible and exposed binding loop leads to dramatic structural changes.
One method of treatment used in cancer therapy is radiotherapy which can injure the oral, pharynx or larynx mucosa and predisposes tissue to the development of fungal infections. The aim of the study paper was the mycological examinations of swabs from the oral cavity and pharynx of patients obtained prior to, in week 3, on the last day of and 3 weeks after radiotherapy, as well as isolation of fungi and identification of the selected parameter of strains pathogenecity, i.e. hydrolytic enzyme release. Forty-three patients with oral cavity, pharynx or larynx carcinoma were examined at four points during a course of radiotherapy: before treatment, in week 3 of treatment, on the last day of treatment and 3 weeks afterwards. The mycological examination was conducted based on a procedure introduced in the Department of Biology and Medical Parasitology, Medical University of Lodz. The activity of the hydrolytic enzymes was evaluated with a bioMerieux API ZYM test kit. More than 2/3 of the patients (68.2%) were found to have a fungal infection in the first examination, 4/5 (80%) in the second, about 3/5 (57.1%) in the third and all (100%) in the last examination. The release of enzymes varied, and on different stages show different inactive enzymes: at the start, α-chymotrypsin and α-mannosidase; at 3 weeks, β-glucuronidase and α-mannosidase; at the end, α-chymotrypsin; at 3 weeks after the end, trypsin, α-chymotrypsin, α-galaktosidase and α-fucosidase. The most frequent species isolated from the patients treated by radiotherapy is Candida albicans and C. glabrata. The latter is characterized by resistance to the majority of antimycotic medications. The isolated strains are characterized by the highest activity of leucine arylamidase, acid phosphatase and naphthol – AS-BI-phosphohydrolase. Considering the enzymes produced, most of the strains can be included to biotypes D₃, C₆ and A.
Concentrations of available phosphorus (PE-R), and sulphate sulphur (S-SO₄²⁻) as well as activities of alkaline (AlP) and acid phosphatase (AcP), and arylsulphatase were assayed in a Luvisol fertilized with various doses (0, 20, 40, 60, 80 t·ha⁻¹) of farmyard manure (factor I) and nitrogen in mineral form (0, 45, 90, 135 kg ha⁻¹, factor II). PE-Rand S-SO₄²⁻ concentrations were significantly affected by fertilization with FYM and nitrogen, with the highest increase noted for soil samples taken from the objects with the manure dose 60 t ha⁻¹. Nitrogen used in the dose 135 kg ha⁻¹ increased significantly S-SO₄²⁻ and decrease PE-Rcontent as compared with their concentrations recorded for lower doses of this fertilizer. The highest concentration of available phosphorus was found in the sample collected in September. However, activities of phosphatases observed in the same sample were the lowest. The lowest arylsulphatase activity was noted in July, while sulphate sulphur concentrations in the same sample was the highest.
The paper presents studies on level hydrolytic activity of extracellular enzymes in the surface microlayer and subsurface water in the coastal lake Dołgie Wielkie. The ranking order of the potential enzyme activity rates in the studied water layers was as follows: aminopeptidase > lipase > α-glucosidase > β-glucosidase. The level of activity of all studied hydrolases was higher in the surface microlayer than subsurface water. Activity of extracellular enzymes was influenced by the season.
W ziarnie zbóż występują w znacznych ilościach białkowe substancje o charakterze inhibitorów enzymów hydrolitycznych. Pomimo, iż występowanie tych substancji w ziarnie zbóż stwierdzono już w latach trzydziestych, to do tej pory nie udało się dokładnie ich poznać. W pracy tej scharakteryzowano inhibitory enzymów amylolitycznych występujące w ziarnie pszenicy, żyta i pszenżyta oraz przedstawiono współczesne poglądy na temat ich znaczenia.
Thermomyces lanuginosus jest jednym z najpowszechniej występujących w przyrodzie grzybów termofilnych. Badania dowodzą, że szczepy tego gatunku zdolne są do biosyntezy wielu enzymów hydrolitycznych. Prace określające aktywność lipolityczną szczepów tego gatunku prowadzone były najczęściej na podłożu z dodatkiem oliwy z oliwek. Celem niniejszego opracowania była ocena zdolności szczepów Thermomyces lanuginosus do biosyntezy egzoenzymów lipolitycznych w obecności tłuszczów o konsystencji stałej.
W pracy przedstawiono przegląd danych literaturowych na temat zbożowych, białkowych inhibitorów enzymów proteolitycznych. Szczególną uwagę zwrócono na ich właściwości, formy wielorakie, a także ich znaczenie biochemiczne, fizjologiczne i żywieniowe.
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