A Continuous Photometric Method for the Determination of Small Intestinal Invertase

Abstract

An easy to perform, rapid and precise assay for invertase is introduced. In it enzyme activity is determined spectrophotometrically from a coupled enzymatic reaction. Ein kontinuierlicher spektrophotometrischer Test für die DünndarminvertaseZusammenfassung: Ein einfacher, rasch durchfuhrbarer und präziser Test für Invertase wird vorgestellt. In ihm wird die Enzymaktivität spektrophotometrisch anhand einer gekoppelten enzymatischen Reaktion gemessen.

A Continuous Automated Method for the Determination of Intestinal Disaccharidase Activities

“…The assays were optimized for pH and substrate concentration for the three enzymes from rat intestinal mucosa. The optimal pH value from the three enzymes was 6.7, a value slightly higher than that reported for human intestinal disaccharidases (pH 6.0) by others [3,6]. The K m values determined in this study were similar for maltase, isomaltase and sucrase from the rat intestine and for disaccharidases of human origin [3,7].…”

“…The optimal pH value from the three enzymes was 6.7, a value slightly higher than that reported for human intestinal disaccharidases (pH 6.0) by others [3,6]. The K m values determined in this study were similar for maltase, isomaltase and sucrase from the rat intestine and for disaccharidases of human origin [3,7]. Sodium ions are known as activators of sucrase [8].…”

“…The aim of this study was to develop a continuous kinetic assay on a commonly used analyzer in clinical laboratories. For this purpose, the glucose dehydrogenase method, initially performed manually at 25°C and only for sucrase [3], was adapted to a Cobas Mira analyzer. Measurements were done at 37°C, the temperature at which Dahlqvist's [1,2] conventional assay was described, in order to allow betweenassay comparison.…”

“…The aim of this study was to develop an automated and reliable assay of disaccharidase activities, which at the same time enables the continuous monitoring of the kinetics of the enzymatic reactions. For this purpose a coupled reaction catalyzed by glucose dehydrogenase was used to determine the glucose generated by three disaccharidase activities as previously proposed by Hansen and Schreyer [3], but only for sucrase. The present application was developed for maltase (·-D-glucoside glucohydrolase, EC 3.2.1.20), isomaltase (dextrin 6-·-D-glucanohydrolase, EC 3.2.1.10) and sucrase (sucrose ·-D-glucohydrolase, EC 3.2.1.48) and was adapted on a Cobas Mira automated analyzer (Roche, Basel, Switzerland).…”

Classic and contemporary approaches to modeling biochemical reactions

“…With a simple enzymatic reaction in vitro, observables such as the rate of formation of product over time might correspond directly to a dynamical variable, but, in more complex models, the connection between data and dynamical variables is more subtle. In cells, most observables are composites of multiple dynamic variables, or they derive from some biosensor whose own biochemistry must be considered (this is analogous to the use of coupled enzymatic reactions as a means to monitor product formation in classical enzymology) (Hansen and Schreyer 1981;Bartelt and Kattermann 1985).…”