Search results for "DASE"
showing 10 items of 1891 documents
Activation of the first component of complement, C1: comparison of the effect of sixteen different enzymes on serum C1.
1983
In this study, the effect of sixteen different enzymes on serum C1 and its subcomponents was investigated. The sixteen enzymes could be divided into three groups. First, enzymes which activate native C1: trypsin (optimal concentration 2.4 x 10(-4) mM); alpha-chymotrypsin (2.3 x 10(3) mM); thrombin (1.0 x 10(-5) mM); plasmin (1.9 x 10(-5) mM); elastase (5.8 x 10(-5) mM); pronase (3.0 x 10(-6) mM). All these enzymes are serine esterase and activate native serum C1 bound to EAC4 at the given concentration within 10 min at 30 degrees C. Furthermore, native C1 inhibited by a pentosanpolysulfoester, Sp54, is unable to undergo the internal activation but can be externally activated by the serine e…
A molecular study of Neophyllaphis varicolor (Hemiptera, Aphididae) in Costa Rica
2019
The genus Neophyllaphis (Takahashi) (Aphididae: Neophyllaphidinae) is composed of 18 species; however, in the Americas only nine species have been reported previously. A new species, Neophyllaphis varicolor Miller & Halbert, was described in 2014 in USA. Colonies resembling those of this new species have been observed in Costa Rica on Podocarpus spp. In order to determine if N. varicolor is also present in Costa Rica, we sampled Neophyllaphis colonies from Podocarpus falcatus and P. chinensis. Additionally, we sampled individuals from Podocarpus sp. in Spain and Vietnam. DNA of each sample was extracted and used to amplify and sequence the cytochrome c oxidase subunit I (COI) and elongation…
Alteration of poly (ADP-Rib) synthesis during progesterone- caused gene expression in oviducts of quails.
1976
Summary The biological model of the selective induction of RNA synthesis in oviducts of estrogen stimulated immature quails by progesterone has been used to clarify whether poly (ADP-Rib) is involved in DNA transcription. The chromatin-bound as well as the soluble poly (ADP-Rib) polymerase has been isolated from oviducts and the optimal reaction conditions have been determined. The activities, as measured by the incorporation rates of NAD + into poly (ADP-Rib), of both, chromatin-bound « endogenouspolymerase (in the absence of « exogenousDNA and histones) and soluble enzyme (native DNA - lysine-rich histone ratio: 4.3) from progesterone treated quail oviducts, have been determined to be onl…
Protein-Based Nanoparticles for the Delivery of Enzymes with Antibacterial Activity.
2018
Proteins represent a versatile biopolymer material for the preparation of nanoparticles due to their biocompatibility, biodegradability, and low immunogenicity. This study presents a protein-based nanoparticle system consisting of high surface PEGylated lysozyme polyethylene glycol-modified lysozyme (LYZmPEG ). This protein modification leads to a solubility switch, which allows a nanoparticle preparation using a mild double emulsion method without the need of surfactants. The method allows the encapsulation of large hydrophilic payloads inside of the protein-based nanoparticle system. Native lysozyme (LYZ) was chosen as payload because of its innate activity as natural antibiotic. The mild…
In situ forming hydrogels of hyaluronic acid and inulin derivatives for cartilage regeneration.
2014
An in situ forming hydrogel obtained by crosslinking of amino functionalized hyaluronic acid derivatives with divinylsulfone functionalized inulin (INU-DV) has been here designed and characterized. In particular two hyaluronic acid derivatives bearing respectively a pendant ethylenediamino (EDA) portion (HA-EDA) and both EDA and octadecyl pendant groups (HA-EDA-C18) were crosslinked through an azo-Michael reaction with INU-DV. Gelation time and consumption of DV portions have been evaluated on hydrogel obtained using HA-EDA and HA-EDA-C18 derivatives with a concentration of 3% w/v and a ratio 80/20 w/w respect to the crosslinker INU-DV. The presence of pendant C18 chains improves mechanical…
Tuning the life-time of supramolecular hydrogels using ROS-responsive telechelic peptide-polymer conjugates
2019
Abstract The synthesis of multi-stimuli responsive peptide-poly(ethylene glycol) ABA-type conjugates is reported. The β-sheet encoded intramolecular folding and intermolecular self-assembly into 1D nanorods is based on a phenylalanine(F)-methionine(M)-histidine(H) FMHMHF hexapeptide sequence, and the supramolecular nanorods are stabilised by a shielding corona of hydrophilic PEG polymers. Interstrand crosslinking leads to the formation of physical networks and hydrogels at physiological pH and at room temperature. The thioether functional groups integrate oxidation responsive properties in the supramolecular polymer assemblies. We show that the glucose fuelled and glucose oxidase catalysed …
Oxidative Copolymerisation ofpara-Functionalized Phenols Catalyzed by Horseradish peroxidase and Thermocrosslinking via Diels-Alder and (1+3) Cycload…
2001
The horseradish peroxidase- (HRP-) catalyzed polyrecombination of N-(4-hydroxyphenyl)-2-furamide (2) and 4-hydroxyphenylmaleimide (1) is described. The resulting copolymer was used to build crosslinked materials via Diels-Alder and cycloaddition reactions. We followed the enzymatic copolymerization process of an equimolar mixture of 1 and 2 using high pressure liquid chromatography (HPLC), size-exclusion chromatography (SEC) and by matrix assisted laser desorption/ionization-time of flight mass spectroscopy (MALDI-TOF MS) analysis and found that the polymerization of 2, which has a significant higher highest occupied molecular orbital (HOMO) energy, proceeds much faster. The HOMO energies o…
Enzymatically catalyzed synthesis of photocrosslinkable oligophenols
2000
The HRP-catalyzed oligomerization of cinnamoyl-hydroquinone-ester and cinnamoyl-4-hydroxyanilide led to the formation of soluble polyphenols. The oligomers were synthexized in water/1,4-dioxane and in water/acetone mixtures and characterized by NMR, FTIR and SEC. Upon UV treatment of the homogenoes films the polyphenols were crosslinked due to [2+2]-cycloadditions of the cinnamoyl functions.
Polarographic determination of tyrosinase activity in enzymatic reaction with tyrosine as a substrate
2003
A voltammetric investigation of tyrosinase activity is proposed as an alternative to the spectrophotometric method. Voltammetric approach provides low detection limit, high sensitivity and resistivity to the solution inhomogenity, as well as enables one to simultaneously monitor the dioxygen consumption in the reaction, which is an additional indicator of the tyrosinase enzymatic activity.
POLYPHENOL OXIDASE ACTIVITY FROM THREE SICILIAN ARTICHOKE (CYNARA CARDUNCULUS L. VAR. SCOLYMUS L. (FIORI)) CULTIVARS: STUDIES AND TECHNOLOGICAL APPLI…
2010
Several papers helped with the development of more methods to control browning, or study thermal polyphenol oxidase (PPO) inactivation, but did not provide any solutions to technological process problems and food process improvement. Artichokes [ Cynara cardunculus L. var. scolymus L. (Fiori)] are susceptible to browning; this alteration could affect and reduce the suitability for its use, fresh or processed. Within this study, the catecholase and cresolase activities of PPO from three different Sicilian artichokes cultivar were characterized with regard to substrate specificity and enzyme kinetics, optimum pH and temperature, temperature and pH stability, and inhibitor test; all of the res…