A galactose oxidase (EC 1.1.3.9):NADH-peroxidase (EC 1.11.1.1) coupled assay system is used for the estimation of galactose oxidase activity. Spectrophotometric measurement of NADH consumption yields direct quantitative value of enzymic activity or can be used for the end-point determination of the
NADH-coupled spectrophotometric assay of diamine oxidase
✍ Scribed by Silvestro Duprè; Sandro P. Solinas; Pietro Guerrieri; Giorgio Federici; Doriano Cavallini
- Publisher
- Elsevier Science
- Year
- 1977
- Tongue
- English
- Weight
- 312 KB
- Volume
- 77
- Category
- Article
- ISSN
- 0003-2697
No coin nor oath required. For personal study only.
✦ Synopsis
A simple spectrophotometric method for estimation of diamine oxidase (DAO) activity was developed, based on a coupled reaction with NADH-dependent alcohol-dehydrogenase.
Cystamine, upon DA0 action, is transformed into an aminoaldehyde which reacts quickly and quantitatively with NADH in the presence of liver alcohol dehydrogenase: oxidation rates at 340 nm are linear, with protein concentration over the whole range of purification steps of DAO. The high sensitivity, the possibility of continuous monitoring, and the easy performance with commercially available products allows this new method to be considered comparable to the most diffuse standard methods.
📜 SIMILAR VOLUMES
## Methods Direct spectrophotometric assay. This was carried out using p-dimethylaminomethylbenzylamine as substrate as previously described (1,111. Indirect spectrophotometric assays. These were carried out as described (2-4,12). A Cary 118C UV-VIS spectrophotometer was used throughout this stud
Chymotrypsin can be determined with an NADH-coupled assay. Hydrolysis of the substrate benzoyhyrosine ethyl ester is monitored by coupling the liberation of ethanol to the production of NADH and determining the NADH spectrophotometrically or fluorometrically. Nanogram quantities of chymotrypsin can