Abstract:
Methods to determine the concentration of gamma-hydroxy butyric acid (GHB) in a sample as well as compositions and a kit suitable for carrying out said methods. Also, the use of the methods for application on a microtiter plate or an auto-analyzer.
Abstract:
The invention relates to a preferably continuous process for the preparation of R- or S-2-hydroxy-4-phenylbutyric acid in very high enantiomeric purity, which comprises reducing 2-oxo-4-phenylbutyric acid with the enzyme D-lactate dehydrogenase from Staphylococcus epidermidis or with the enzyme L-lactate dehydrogenase from bovine heart, respectively, in the presence of NAD(H) and formate or ethanol and formate dehydrogenase or alcohol dehydrogenase, respectively. R-2-hydroxy-4-phenylbutyric acid is a valuable intermediate in the preparation of ACE inhibitors or their precursors.
Abstract:
Methods to determine the concentration of gamma-hydroxy butyric acid (GHB) in a sample as well as compositions and a kit suitable for carrying out said methods. Also, the use of the methods for application on a microtiter plate or an auto-analyzer.
Abstract:
The invention relates to methods for the determination of vitamin B6 in samples as well as to reagent compositions for assaying a sample for vitamin B6 and to a test kit suitable for carrying out the methods according to the present invention. Further, the invention relates to the use of such methods for the application to different analyzing devices such as micro-titer plate readers and fully automated clinical chemistry analyzers (autoanalyzers).
Abstract:
The invention relates to methods for the determination of vitamin B6 in samples as well as to reagent compositions for assaying a sample for vitamin B6 and to a test kit suitable for carrying out the methods according to the present invention. Further, the invention relates to the use of such methods for the application to different analyzing devices such as micro-titer plate readers and fully automated clinical chemistry analyzers (autoanalyzers).
Abstract:
A process for obtaining N-acetylneuraminic acid from N-acetylglucosamine is disclosed. The process is carried out in a reactor which contains both N-acylglucosamine-2-epimerase (E.C. 5.1.3.8) which isomerizes GlcNAc into ManNAc, and N-acetylneuraminic acid pyruvate lyase (E.C. 4.1.3.3) which catalyzes the reaction of the resulting ManNAc with pyruvic acid to give Neu5Ac. GlcNAc and Pyr are fed into the reactor and Neu5Ac is obtained in the outflow. The process is preferably carried out continuously and in particular in an enzyme membrane reactor at pH 7.5 and 25.degree. C., especially using residence times of 0.2 to 10 h, and with an excess of GlcNAc in comparison with Pyr which is subsequently added if necessary. Epimerase and lyase are preferably present in the reactor in a ratio of activities which is equivalent to the reciprocal value of the quotient of the conversion rates.