Chromatography of human plasma on aminohexyl Sepharose: separation of factor VIII/vWf and behaviour of factors II, VII, IX and X and antithrombin III

Human plasma was chromatographed under different experimental conditions on aminohexyl Sepharose. A strong retention of factor VIII/vWf and of factors VII, II, IX and X was observed. A satisfactory stabilization of eluted factor VIII clotting activity was obtained after addition of albumin and sucrose to the buffers used during chromatography. Albumin and antithrombin III were found apparently intact in the column effluent.     

Crystal and molecular structure ofl-3-(2-acetamido-2-ethoxycarbonyl)ethylindole

l-3-(2-Acetamido-2-ethoxycarbonyl)ethylindole is monoclinic:a = 11.469(8),b = 8.088(6),c = 8.457(6) Å, = 106.45(7) °,Z = 2,P2₁. The structure has been solved by direct methods with CuK three-dimensional photographic data, and refined by full-matrix least squares toR = 0.097 for 1390 observed reflections. The structure is stabilized by intermolecular N-H...O hydrogen bonds. The indole ring of the molecule is planar within experimental error.Contribution No. 440 from the Department of Crystallography and Biophysics, University of Madras, Guindy Campus Madras-600025, India.     

Studies in molecular structure,symmetry and conformation VII. Crystal structure of 4,4′-diaminodiphenylsulphide

The crystal structure of 4,4-diaminodiphenylsulphide, C₁₂H₁₂N₂S, has been determined by three-dimensional X-ray methods. The crystals are orthorhombic, with space-groupP2₁2₁2₁,a = 9·874(6),b = 19·445(9),c = 5·876(6) andZ= 4. The structure was solved by the heavy-atom method and refined by full-matrix least squares to anR value of 0·074. The molecules are held together by hydrogen bonds of the N-H N type, and form chains parallel to theb axis.Contribution No. 354 from the Centre of Advanced Study in Physics, University of Madras-600025, India.     

Purification of ß-glucosidases from <Emphasis Type="Italic">Pichia etchellsii</Emphasis> Using CIM Monolith Columns

β-Glucosidases (EC 3.2.1.21) are industrially important glycosyl hydrolases used for cellulose saccharification as well as for synthesis of glyco-conjugates. Crystal structure of only one β-glucosidase of family 3 of the glycosyl hydrolase families is available due to difficulty in purification of these closely related enzymes from a given source. Multiple steps used during purification result in low yield, making it difficult to study their properties. Conditions for purification of two closely related β-glucosidases (BGL I and BGL II) of family 3 from Pichia etchellsii were investigated in this study. Two weak anion exchange columns convective interaction media-diethyl amino ethyl (CIM-DEAE) and CIM-ethylenediamine (CIM-EDA) were used for this purpose. The results obtained at 0.34 ml disk (CIM-DEAE) level were scaled up to 8 ml CIM-DEAE tube column wherein BGL I and BGL II were separated from the major contaminants in the cell-free extract. The recovered enzymes were completely resolved in the second step using CIM-EDA. A final specific activity of 9,180 IU/mg and 2,345.3 IU/mg was achieved for BGL I and BGL II respectively with an overall yield of 33%. The system should be applicable to resolution of other closely related enzymes from this family.     

Electron irradiation effects on 4-amino-5-mercapto-3-[1-(4-isobutylphenyl)ethyl]-1,2,4-triazole single crystal

In this paper, we report the electron irradiation effects on the properties of an organic NLO single crystal of 4-amino-5-mercapto-3-[1-(4-isobutylphenyl)ethyl]-1,2,4-triazole. The crystal was irradiated with electron beam of different doses and was characterized by powder XRD, UV-Vis, FTIR, DSC, microhardness and SHG measurements. In XRD, the peaks are shifted due to irradiation. The SHG efficiency has been found to enhance rapidly with irradiation. The investigation of the influence of electron irradiation on the surface morphology of the grown crystal reveals the formation of craters on the surface. The laser damage threshold remains constant as the dose rate increases whereas refractive index increases after irradiation.     

A simple uric acid assay by using 3-hydroxytyramine as a chromogenic colorimetric sensor in human serum samples: Density functional theory supported mechanistic approach

A simple, fast, sensitive, convenient, and economical accurate enzymatic colorimetric sensor is developed for the quantification of the clinically important biomarker uric acid (UA) in human serum samples. The method is based on the quantification of UA using 3-hydroxytyramine (3-HT) as a chromogenic substrate by using peroxidase (POD) and uricase (UOx). UOx catalyzes the oxidation of UA where H₂O₂ is generated in-situ to produce allantoin and CO₂. The POD in oxidative coupling of peroxide in presence of 3-HT, forms an intense orange-colored product with λ_max = 500 nm. The reaction was carried out in a citric acid-tripotassium-citrate buffer (12.5 mM) of pH = 6.8 at room temperature. Computational calculations were done by Gaussian-16 employing the B3LYP functional basis set. The standard curve for UA was found to be linear between 12.3–297.3 and 3.07–396.5 μM by rate and fixed time method, respectively. The LOD and LOQ for UA were 1.5 and 2.9 μM, respectively. Within-day and day-to-day precision was 1.50–3.07 and 3.10–4.16% (n = 7), respectively. The accuracy ranges for UA concentrations of 24.7, 198 and 297.3 μM were 87%–101.50%, 90%–105%, and 89%–107%, respectively. The UA recovery range by the proposed method was 98.00%–100.47% with a mean recovery of 99.5% and has A good correlation coefficient of 0.981 with the standard method.