An Improved Colorimetric Assay for Bacterial Lipase in Nonfat Dry Milk

Abstract

A modification of McKellar and Cholette's (1986) calorimetric method for determining lipase activity in reconstituted non-fat dry milk was develooed. The method uses the color reaction between Fast Blue BB and the S-naphthol (BN) enzymatically cleaved from f3-naphthyl cap@ate (BNC) as a measure of lipase activity. In the modified method, a solvent system is used to clarify the sample rather than extracting the colored product. This modification allows measurement of total sample lipase by excluding centrifugation. In addition, the modified method has greater sensitivity with equal ease of use.

Effect of β-Glucans in Diets on Growth, Survival, Digestive Enzyme Activity, and Immune System and Intestinal Barrier Gene Expression for Tropical Gar (Atractosteus tropicus) Juveniles

“…Tris-HCl buffer solution (pH = 7.2) [67]. The lipolytic activity is defined as 1 μg of naphthol released per minute with a MEC of 0.02 cm −1 M −1 .…”

“…A unit was defined as the amount of enzyme that releases 1 µg of maltose per minute [66]. The lipase activity was determined using as substrate β-naphthylcaprylate (200 mmol L −1 ) dissolved in a 50 mmol L −1 Tris-HCl buffer solution (pH = 7.2) [67]. The lipolytic activity is defined as 1 µg of naphthol released per minute with a MEC of 0.02 cm −1 M −1 .…”

“…A unit of enzymatic activity w ƿ-nitroanilide released per minute with a MEC of 8800 cm −1 M −1 [65]. Th determined using starch as substrate in citrate-phosphate buffer 100 mmol unit was defined as the amount of enzyme that releases 1 μg of maltose pe activity was determined using as substrate β-naphthylcaprylate (200 mm mmol L −1 Tris-HCl buffer solution (pH = 7.2) [67]. The lipolytic activity is de released per minute with a MEC of 0.02 cm −1 M −1 .…”

Circadian cycle of digestive enzyme production at fasting and feeding conditions in Nile tilapia, Oreochromis niloticus (Actinopterygii: Perciformes: Cichlidae)

“…One unit of chymotrypsin activity was defi ned as the enzyme required to release 1 μmol of 4-nitroanilide · min -1 . Lipase activity was determined using β-naphthyl caprylate as substrate (Versaw et al 1989). The reaction mixture consisted of 100 μL sodium taurocholate (100 mmol), 1900 μL Tris HCl (200 mmol, pH 8), 10 μL enzyme extract and 10 μLβ-naphthyl caprylate (#N8875, Sigma-Aldrich) (100 mmol in DMSO), as substrate.…”

Effect of dietary chitin on digestive enzyme activity, growth and survival of Macrobrachium tenellum juvenile prawns

“…Bovine serum albumin (05470, Sigma-Aldrich, St. Louis, MO) was used as the protein standard. Lipase activity was determined as described by Versaw et al (1989), using β-naphthyl caprylate as the substrate. Lipase activity was expressed as lipase units mg -1 protein (one lipase unit was the quantity of enzymes required for an increase of 0.01 absorbance units at 540 nm min -1 ).…”