P-Nitrophenol-alpha-D-glucopyranoside as substrate for measurement of maltase activity in human semen.

1978 ◽  
Vol 24 (2) ◽  
pp. 208-211 ◽  
Author(s):  
P Chapdelaine ◽  
R R Tremblay ◽  
J Y Dubé
Keyword(s):  
Seminal Plasma ◽  
Reduced Glutathione ◽  
Rapid Determination ◽  
Potassium Phosphate ◽  
Potassium Phosphate Buffer ◽  
Michaelis Constant ◽  
Maltase Activity ◽  
Constant Rate ◽  
Hydrolysis Of

Abstract Hitherto, seminal plasma maltase has been measured with maltose as substrate; this method is time consuming and lacks specificity. The use of a synthetic substrate, p-nitrophenol-alpha-D-glucopyranoside, allows accurate and rapid determination of this activity. When maltase is added to the incubation medium (the substrate and reduced glutathione in potassium phosphate buffer, pH 6.8), maintained at 37 degrees C, hydrolysis of the original substrate to p-nitrophenol goes at a constant rate during 4 h. Under optimal conditions of incubation, the Michaelis constant of the reaction, calculated by the Hanes method, was 2.92 +/- 0.84 (SD) X 10(-3) for six different semen samples. Isomaltase appeared to be absent from seminal plasma. The enzyme is stable to freezing and slow thawing and can be stored for at least 26 days at -80 degrees C. Its molecular weight is 259 000. Tris(hydroxymethyl)aminomethane (pH 6.8) exerts a noncompetitive inhibition on the enzyme activity. In 68 men 23 to 45 years old, whose semen analyses were normal, the seminal plasma maltase activity was 467 +/- 135 (SD) mU/g of protein. It was generally decreased in patients with infertility disorders.

HPLC method for measurement of purine nucleotide degradation products in cerebrospinal fluid

1996 ◽  
Vol 42 (5) ◽  
pp. 756-760 ◽  
Author(s):  
L Kuracka ◽  
T Kalnovicová ◽  
B Líska ◽  
P Turcáni
Keyword(s):  
Cerebrospinal Fluid ◽  
Uric Acid ◽  
Neurological Disorders ◽  
Limit Of Detection ◽  
Degradation Products ◽  
Potassium Phosphate ◽  
Hplc Method ◽  
Potassium Phosphate Buffer ◽  
Nucleotide Degradation

Abstract We describe a convenient method for the separation and quantification of xanthine, hypoxanthine, and uric acid in 20 microL of cerebrospinal fluid (CSF) with use of HPLC and ultraviolet detection. The analysis is performed on a Sepharon SGX C18 column and the elution system consists of potassium phosphate buffer, pH 5.1, with 20 mL/L methanol. The lower limit of detection was 4 pmol for hypoxanthine and xanthine and 6 pmol for uric acid. Analytical recoveries of purine metabolites ranged from 98.6% to 102.9%. The intra- and interassay CVs were <3%. The applicability of the method is illustrated with the determination of micromolar concentrations of xanthine, hypoxanthine, and uric acid in CSF samples obtained from 113 patients with various neurological disorders.

Simple and Rapid Determination of Phytase Activity

1994 ◽  
Vol 77 (3) ◽  
pp. 760-764 ◽  
Author(s):  
Adrianus J Engelen ◽  
Fred C Van Der Heeft ◽  
Peter H G Randsdorp ◽  
Ed L C Smtt
Keyword(s):  
Enzymatic Activity ◽  
Rapid Method ◽  
Rapid Determination ◽  
Phytase Activity ◽  
Sodium Phytate ◽  
Microbial Phytase ◽  
Hydrolysis Of

Abstract A simple and rapid method is described for determining the enzymatic activity of microbial phytase. The method is based on the determination of inorganic orthophosphate released on hydrolysis of sodium phytate at pH 5.5.

Simple, rapid determination of zinc and acid phosphatase in seminal plasma with an ABA-100 bichromatic analyzer.

1988 ◽  
Vol 34 (8) ◽  
pp. 1605-1607 ◽  
Author(s):  
M Gavella
Keyword(s):  
Acid Phosphatase ◽  
Male Infertility ◽  
Seminal Plasma ◽  
Rapid Determination ◽  
Assay System ◽  
Human Seminal Plasma ◽  
Automated Assay ◽  
Sensitivity Specificity

Abstract I describe an automated assay for zinc and acid phosphatase in seminal plasma. These, which are markers of the function of the prostate, were assayed bichromatically with an Abbott ABA-100 analyzer. As many as 25 samples of human seminal plasma can be analyzed sequentially with CVs of 3.1% for zinc and 1.5% for acid phosphatase. The sensitivity, specificity, and speed of this assay system make it practicable for use in investigation of male infertility.

Determination of Neomycin in Animal Tissues, Using Ion-Pair Liquid Chromatography with Fluorometric Detection

1985 ◽  
Vol 68 (1) ◽  
pp. 29-36
Author(s):  
Badar Shaikh ◽  
Edward H Allen ◽  
John C Gridley
Keyword(s):  
Mobile Phase ◽  
Potassium Phosphate ◽  
Internal Standard ◽  
Ion Pair ◽  
Fluorometric Detection ◽  
Animal Tissues ◽  
Potassium Phosphate Buffer ◽  
Reverse Phase ◽  
Liquid Chromatographic

Abstract A liquid chromatographic (LC) method is described for the determination of neomycin in animal tissues. Tissues are homogenized in 0.2M potassium phosphate buffer (pH 8.0); the homogenate is centrifuged, and the supernate is heated to precipitate the protein. The heat-deproteinated extract is acidified to pH 3.5-4 and directly analyzed by LC. The LC method consists of an ion-pairing mobile phase, a reverse phase ODS column, post-column derivatization with o-phthalaldehyde reagent, and fluorometric detection. The LC method uses paromomycin as an internal standard, and separates neomycin from streptomycin or dihydrostreptomycin because they have different retention times. The LC column separates neomycin in 25 min; the detection limit is about 3.5 ng neomycin. The overall recovery of neomycin from kidney tissues spiked at 1-30 ppm was 96% with a 9.0% coefficient of variation. The method was also applied to muscle tissue.

Morphology and biodegradability of a binary blend of poly((R)-3-hydroxybutyric acid) and poly((R,S)-lactic acid)

1995 ◽  
Vol 41 (13) ◽  
pp. 316-322 ◽  
Author(s):  
Naoyuki Koyama ◽  
Yoshiharu Doi
Keyword(s):  
Differential Scanning Calorimetry ◽  
Lactic Acid ◽  
Enzymatic Hydrolysis ◽  
Potassium Phosphate ◽  
Hydroxybutyric Acid ◽  
Potassium Phosphate Buffer ◽  
Scanning Calorimetry ◽  
Binary Blend ◽  
Blend Films ◽  
Hydrolysis Of

The miscibility, morphology, and biodegradability of a binary blend of bacterial poly((R)-3-hydroxybutyric acid) (P((R)-3HB); Mn = 300 000) with atactic poly((R,S)-lactic acid) (P((R,S)-LA); Mn = 9000) were studied by means of differential scanning calorimetry, optical microscopy, scanning electron microscopy, and hydrolysis with and without enzyme. Differential scanning calorimetry revealed that a P((R)-3HB)–P((R,S)-LA) blend had a single glass-transition temperature for all proportions of the components. The spherulites of P((R)-3HB) were volume filled in the blend films, indicating the inclusion of amorphous P((R,S)-LA) within the spherulites. The spherulitic growth rate decreased with an increase in the content of P((R,S)-LA). These results indicate that the P((R)-3HB)–P((R,S)-LA) blend is miscible in the melt and in the amorphous state. The enzymatic hydrolysis of P((R)-3HB)–P((R,S)-LA) blend films was carried out at 37 °C for 19 h in 0.1 M potassium phosphate buffer (pH 7.4) with an extracellular poly(hydroxybutyrate) depolymerase from Alcaligenes faecalis T1. The rate of enzymatic surface erosion decreased with increasing P((R,S)-LA) content in the blend films. The simple hydrolysis of P((R)-3HB)–P((R,S)-LA) blend films without enzyme was also conducted at 37 °C in a 0.01 M potassium phosphate buffer (pH 7.4) for 150 days. The hydrolytic scission of P((R)-3HB) polymer chains was accelerated by blending with P((R,S)-LA). However, the rate of enzymatic hydrolysis was much faster than the rate of nonenzymatic hydrolysis.Key words: poly((R)-3-hydroxybutyric acid), poly((R,S)-lactic acid), miscibility, morphology, biodegradability.

Flow injection-chemiluminescent assay for the determination of superoxide dismutase activity

2001 ◽  
Vol 79 (3) ◽  
pp. 337-341
Author(s):  
Hong Yeob Choi ◽  
Jin Hyang Song ◽  
Yong Sung Park ◽  
Gabriel Lord ◽  
Dong Ki Park
Keyword(s):  
Superoxide Dismutase ◽  
Xanthine Oxidase ◽  
Flow Injection ◽  
Mobile Phase ◽  
Potassium Phosphate ◽  
Optimum Conditions ◽  
Potassium Phosphate Buffer ◽  
Sod Activity ◽  
Relative Standard

Superoxide dismutase (SOD) activity was measured using a flow injection-chemiluminescent assay (FI-CLA) based on xanthine–xanthine oxidase dependent superoxide (O2.–) formation. The mobile phase consists of 50 mM potassium phosphate buffer (pH 7.4) containing lucigenin (5 µM) and xanthine (0.3 mM). Under optimum conditions, bovine albumin did not affect chemiluminescence at concentrations of 1–1000 µg mL–1 and KCN inhibited 100% of the Cu, Zn-SOD activity using 5 µL of a 0.23 mM concentration. The analysis of one sample was done in less than 30 s with a relative standard deviation of ±3.1%. SOD activity in the biological samples was correlated to the amount of exogenously applied SOD. The FI-CLA method reported here appears to be one of the faster and more useful tools used to assay SOD activity.Key words: superoxide dismutase, flow injection-chemiluminescent assay, superoxide, xanthine oxidase, lucigenin.

Simultaneous liquid-chromatographic determination of hypoxanthine, xanthine, urate, and creatinine in cerebrospinal fluid, with direct injection.

1983 ◽  
Vol 29 (8) ◽  
pp. 1543-1546 ◽  
Author(s):  
F Niklasson
Keyword(s):  
Cerebrospinal Fluid ◽  
Direct Injection ◽  
Potassium Phosphate ◽  
Chromatographic Determination ◽  
Reversed Phase ◽  
Potassium Phosphate Buffer ◽  
Liquid Chromatographic Determination ◽  
Phase Liquid ◽  
Liquid Chromatographic

Abstract In this method for simultaneously determining hypoxanthine, xanthine, urate, and creatinine in cerebrospinal fluid, centrifuged sample is directly injected on a reversed-phase liquid-chromatographic column. On elution with potassium phosphate buffer the compounds are quantified by their absorbance at 260 nm. Random error (CV) was between 1.2 and 3.4% and analytical recoveries were 99-104% at physiological concentrations.

scholarly journals Development and Validation of an HPLC Method for Mefloquine Hydrochloride Determination in Tablet Dosage Form

2011 ◽  
Vol 94 (4) ◽  
pp. 1089-1093 ◽  
Author(s):  
Fernando Henrique Andrade Nogueira ◽  
Letícia De Paula Lana Goulart ◽  
Isabela Da Costa César ◽  
Lígia Maria Moreira De Campos ◽  
Gérson Antônios Pianetti
Keyword(s):  
Mobile Phase ◽  
Degradation Products ◽  
Potassium Phosphate ◽  
Hplc Method ◽  
Stability Studies ◽  
Potassium Phosphate Buffer ◽  
Photolytic Degradation ◽  
Development And Validation ◽  
Tablet Dosage

Abstract A simple HPLC method for determination of mefloquine hydrochloride in tablets was developed and validated. The separation was carried out on an Xterra RP18 (250 × 4.6 mm id, 5 µm particle size) analytical column. The mobile phase was 0.05 M monobasic potassium phosphate buffer (pH 3.5)–methanol (40 + 60, v/v). The flow rate and wavelength were set to 1 mL/min and 283 nm, respectively. The method was specifc for mefloquine hydrochloride in the presence of hydrolytic, oxidative, and photolytic degradation products. It was also linear, precise, accurate, and robust, being suitable for routine QC analyses and stability studies. The developed HPLC method was compared to a previously described spectrophotometric method.

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