We present a rate-determination method for analyzing glucose. A glucose enzyme electrode serves as the sensor and is made by placing a gel-immobilized layer of glucose oxidase over the tip of a Clark-type O2 electrode. The electrode membrane is made of Teflon and is derivatized by etching with a suspension of colloidal sodium metal in organic solvent. The enzyme is coupled to the membrane surfa...

This is an adaptation of the Fujirebio "ACEcolor" kit for automated measurement of angiotensin-converting enzyme (EC 3.4.15.1) in serum with the Cobas Fara centrifugal analyzer. The linear range extends to an activity of 110 U/L. Results obtained by the present method and by the manual method were identical, and correlated closely (r = 0.983) with those by Cushman's modified method. The referen...

Pancreatin is a biotechnological product containing an enzyme complex, obtained from porcine pancreas, that is employed in treating pancreatic diseases. Experiments regarding the stability of the pharmaceutical formulation containing pancreatin were performed using standard binary mixtures with 6 excipients in a 1:1 ratio (m/m) and a commercial formulation. To accomplish these goals, samples we...

This coupled-enzyme method for determining the activity of catalase (EC 1.11.1.6) in erythrocyte lysates is based on measuring the absorbance at 340 nm of NADH produced from the peroxidic reaction between ethanol, hydrogen peroxide, and catalase. Hydrogen peroxide is produced as a substrate in situ from the oxidation of glucose catalyzed by glucose oxidase (EC 1.1.3.4). Catalase oxidizes ethano...

The determination of an absolute enzyme concentration in a physiological sample is principally straightforward; the main problem is the need for a puriRed sample to use as a standard. Enzymes are proteins found in nature in complex mixtures, usually in cells which perhaps contain several hundreds of different enzymes. In order to understand and interpret enzyme data from complex biological syst...

A convenient and accurate procedure for determining the kinetic parameter Vmax./Km is described. This avoids the error in the usual method of taking the observed first-order rate constant of an enzymic reaction at low substrate concentration as Vmax./Km. A series of reactions is used in which the initial concentration of substrate is below Km (e.g. from 5% to 50% of Km). Measurements are taken ...

Patients' sera were analyzed for digoxin by using two different radioimmunoassays and an enzyme immunoassay. Quantitative results obtained by enzyme immunoassay (I) were compared to results obtained on aliquots of the same sample by the radioimmunoassays (II and III). The correlation coefficients were: I vs. II 0.90, n=108; I vs. III 0.94, n=102; and II vs. III 0.95, n=158. Day-to-day precision...

An enzyme-immunoassay using horseradish peroxidase as label is described. The assay has a sensitivity of 0.1-20 pmol, i.e. 0.03-0.63 ng and intra- and inter-assay coefficients of variation of less than 10% when used for the determination of progesterone in samples of milk from cows. Comparison with a radio-immunoassay based on tritiated tracer showed excellent correlation (r = 0.98) for milk sa...

introduction: α-amylase is a major form of amylase found in humans and other mammals. it is the special key enzyme involved in carbohydrates breakdown. inhibition of this enzyme could be used in treatment of diabetes. in this study, the effect of ten iranian macrolichens on alpha amylase were tested. methods: different concentrations of the extracts (25, 50 and 75 mg/ml) were incubated with enz...

A highly sensitive sandwich-type chemiluminescence enzyme immunoassay for plasma endothelin-I (ET-1), involving no extraction steps, has been developed. Two populations of polyclonal antibodies were used in the present study: One is specific to the C-terminus of the endothelin family of peptides; the other, a Fab' fragment against the N-terminal core region of ET-1, is coupled with horseradish ...