Enzymatic determination of D-alanine with L-alanine dehydrogenase and alanine racemase

2021 ◽  
Author(s):  
Hiroyuki Ashida ◽  
Yoshihiro Sawa ◽  
Tohru Yoshimura
Keyword(s):  
Water Soluble ◽  
Enzymatic Assay ◽  
Assay System ◽  
Alanine Racemase ◽  
Alanine Dehydrogenase ◽  
Enzymatic Determination

Abstract An enzymatic assay system of D-Ala, which is reported to affect the taste, was constructed using alanine racemase and L-alanine dehydrogenase. D-Ala is converted to L-Ala by alanine racemase and then deaminated by L-alanine dehydrogenase with the reduction of NAD+ to NADH, which is determined with water-soluble tetrazolium. Using the assay system, the D-Ala contents of seven crustaceans were determined.

Enzymatic determination of uric acid using water-soluble CuInS/ZnS quantum dots as a fluorescent probe

2018 ◽  
Vol 185 (11) ◽  
Author(s):  
Fangmei Zhang ◽  
Pinyi Ma ◽  
Xinyu Deng ◽  
Ying Sun ◽  
Xinghua Wang ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Uric Acid ◽  
Fluorescent Probe ◽  
Water Soluble ◽  
Enzymatic Determination

Interference by endogenous glycerol in an enzymatic assay of phosphatidylglycerol in amniotic fluid.

1988 ◽  
Vol 34 (3) ◽  
pp. 560-563 ◽  
Author(s):  
D A Herold ◽  
A E Reed
Keyword(s):  
Amniotic Fluid ◽  
Fetal Lung ◽  
Enzymatic Assay ◽  
Glycerol Concentration ◽  
Glycerol Content ◽  
Important Indicator ◽  
Enzymatic Determination ◽  
Total Glycerol ◽  
Lung Maturity

Abstract We investigated the possibility of interference by endogenous glycerol with the enzymatic measurement of phosphatidylglycerol in amniotic fluid. Phosphatidylglycerol is an important indicator of fetal lung maturity. The concentrations of glycerol and phosphatidylglycerol in amniotic fluid were measured by using a coupled enzymatic assay with and without phospholipase D (EC 3.1.4.4). The precision of the assay was acceptable (within-run CV = 1.2%, between-run CV = 4.8%). Endogenous glycerol content was demonstrated to be approximately 10-20 times that of phosphatidylglycerol. This high proportion of endogenous glycerol in amniotic fluid would preclude the accurate enzymatic determination of amniotic fluid phosphatidylglycerol unless the glycerol is first removed. Nor can the actual phosphatidylglycerol concentration be determined by subtracting the endogenous glycerol concentration from the total glycerol, which includes that glycerol derived from phosphatidylglycerol. With a usual range of 9 +/- 7 mumol/L, the error for a given phosphatidylglycerol measurement of +/- 6.6 mumol/L (+/- 2 SD) clearly is too high for this assay to be clinically useful. There was no correlation between concentration of endogenous glycerol or apparent phosphatidylglycerol in amniotic fluid and the lecithin/sphingomyelin ratio of the sample.

Enzymatic determination of D-mannose in serum.

1984 ◽  
Vol 30 (2) ◽  
pp. 293-294 ◽  
Author(s):  
K Soyama
Keyword(s):  
Healthy Volunteers ◽  
Glucose Oxidase ◽  
Fungal Infections ◽  
Enzymatic Assay ◽  
Glucosephosphate Isomerase ◽  
Enzymatic Determination ◽  
Endogenous Glucose ◽  
Glucose 6 Phosphate Dehydrogenase

Abstract A new and simple enzymatic assay for measuring D-mannose in serum is described. Endogenous glucose is eliminated from serum by use of glucose oxidase (EC 1.1.3.4) and catalase (EC 1.11.1.6). D-Mannose concentration is calculated from the increase in NADH formation after mannosephosphate isomerase (EC 5.3.1.8) is added. This increase is a result of coupling the following series of enzymes: hexokinase (EC 2.7.1.1), glucosephosphate isomerase (EC 5.3.1.9), and glucose-6-phosphate dehydrogenase (EC 1.1.1.49, NAD+-dependent). The study included subjects who were healthy volunteers and patients with suspected or proven fungal infections.

Ames Award Lecture 1972. An Investigation of the Determination of Serum Cholesterol by an Enzymatic Method

1973 ◽  
Vol 10 (1-6) ◽  
pp. 79-84 ◽  
Author(s):  
Heather M. Flegg
Keyword(s):  
Serum Cholesterol ◽  
Enzymatic Assay ◽  
Total Serum ◽  
Total Serum Cholesterol ◽  
Enzymatic Method ◽  
Enzymatic Determination ◽  
Cholesterol Determination

The enzymatic determination of total serum cholesterol is described. The source of the enzyme cholesterol dehydrogenase is the bacterium Nocardia erythropolis. A comparison is made between the enzymatic assay and an automated Liebermann-Burchard serum cholesterol determination.

Enzymatic Determination of Hydroxysteroids in Human Skin Surface Lipids1

1963 ◽  
Vol 41 (5) ◽  
pp. 265-268 ◽  
Author(s):  
Thomas J Cook ◽  
Allan L Lorincz ◽  
Alan R Spector
Keyword(s):  
Human Skin ◽  
Skin Surface ◽  
Enzymatic Determination

Quantitative Determination of Plasminogen

1970 ◽  
Vol 23 (02) ◽  
pp. 191-201 ◽  
Author(s):  
H. D Bruhn ◽  
L Müller ◽  
F Duckert
Keyword(s):  
Quantitative Determination ◽  
Plasminogen Activator ◽  
Assay System ◽  
Two Stage ◽  
System Activation ◽  
Frozen Plasma

SummaryA modification of the caseinolytic assay for plasminogen is described. This assay system is characterized by the following features :1. Urokinase is used as activator achieving a complete activation of the plasminogen whereas with streptokinase caseinolytically inactive plasminogen-activator complexes are formed.2. All incubation times are reduced to the minimum which is still compatible with accuracy.3. Results are expressed in percent of a standard of ten normal plasmas.4. In this two-stage assay-system (activation of plasminogen to plasmin, digestion of casein by plasmin) both stages proceed simultaneously in the same system, thus the plasmin formed is stabilized “in statu nascendi” by the casein.5. Several conditions (stability of plasminogen in frozen plasma, use of anticoagulants, reproducibility) are defined.

Simultaneous Spectrophotometric Determination of Salbutamol by Coupling with Diazotized 4-Aminobenzoic acid

2017 ◽  
Vol 8 (1) ◽  
Author(s):  
Hind Hadi ◽  
Gufran Salim
Keyword(s):  
Pharmaceutical Preparations ◽  
Coupling Reaction ◽  
Dosage Forms ◽  
Water Soluble ◽  
Trace Determination ◽  
Aminobenzoic Acid ◽  
Optimum Conditions ◽  
Colored Product ◽  
Versus Concentration

A simple, rapid and sensitive spectrophotmetric method for trace determination of salbutamol (SAL) in aqueous solution and in pharmaceutical preparations is described. The method is based on the diazotization coupling reaction of the intended compound with 4-amino benzoic acid (ABA) in alkaline medium to form an intense orange, water soluble dye that is stable and shows maximum absorption at 410 nm. A graph of absorbance versus concentration indicates that Beer’s law is obeyed over the concentration range of 0.5-30 ppm, with a molar absorbtivity 3.76×104 L.mol-1 .cm-1 depending on the concentration of SAL. The optimum conditions and stability of the colored product have been investigated and the method was applied successfully to the determination of SAL in dosage forms.

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