Determination of α-Amylase, Trypsin and Lipase in Duodenal Fluid: Comparison of Methods

Abstract

The three most important enzymes present in duodenal fluid, α-amylase, trypsin and lipase, were determined by two different methods. Various dilution fluids for these determinations were compared. Some kinetic data are described together with the reproducibility of the assays. For α-amylase the Phadebas method was compared with an UV method. Trypsin was determined using an immunoreactive trypsin test and a titrimetric method, while lipase was determined with a titrimetric method and a Cu-soap method.There was very good agreement between the two α-amylase methods and between the two trypsin determinations. There was also good agreement between both lipase methods.The advantages and disadvantages of all the methods are discussed. Bestimmung von a-Amylase, Trypsin und Lipase in Duodenalsaft: Ein Vergleich von MethodenZusammenfassung: Die drei wichtigsten Enzyme im Duodenalsaft, α-Amylase, Trypsin und Lipase, wurden mit zwei verschiedenen Methoden bestimmt. Es wird ein Vergleich zwischen verschiedenen Fl ssigkeiten zur Verd nnung gezogen. Einige kinetische Angaben werden zusammen mit der Reproduzierbarkeit beschrieben. F r α-Amylase wird ein Vergleich zwischen der Phadebas Methode und einer UV-Methode gezogen. Trypsin wurde mit dem Test auf immunoreaktives Trypsin und einer Titrationsmethode bestimmt, w hrend Lipase mit einer Titrationsmethode und einer Cu-Seifen-Methode bestimmt wurde. Der Vergleich von beiden α-Amylase-Methoden war gut, ebenfalls zwischen beiden Trypsin-und beiden Lipase-Methoden.Die Vorteile und Nachteile aller Methoden werden besprochen.

Lipase Assays

“…Precision is afforded by careful preparation and assaying of reagent blanks. The coefficient of variation in analyses of lipase activity using titrimetry is on the order of 5% to 10% (Benzonana and Desnuelle, ; Hafkenscheid et al, ).…”

“…This partitioning is solvent dependent and compromises some degree of sensitivity of the assay. However, the results from the colorimetric and titrimetric procedures correlate highly (Hafkenscheid et al, ). The estimated coefficient of variation for results from the copper soap procedure is ∼5% (Lowry and Tinsley, ).…”

“…Lipases (triacylglycerol acylhydrolase, EC 3.1.1.3) have broad applications in the food, oleochemical, pharmaceutical, and detergent industries, as well as in diagnostic settings (Hafkenscheid et al, ; Schmid and Verger, ). Over 100 lipases have been characterized to some extent, and more than 30 of these are commercially available.…”

Measurement of Pancreatic and Salivary Alpha-Amylase in Serum: Comparison of Methods with Five Different Substrates

“…These samples were taken by an oropharyngeal tube with its orifice at the duodenal-jejunal transition. The pancreas was stimulated by a meal (Lundh test) [14]. a-Amylase from human saliva was collected sublingually by con tinuous aspiration into a collection tube.…”

“…The saliva was centrifuged to remove particulate material. The duodenal fluid and the saliva (own standards) were stored at -20 °C and diluted as described earlier [14]. Venous blood was sampled from normal human voi- …”