A single and continuous spectrophotometric assay for various lipolytic enzymes, using natural, non-labelled lipid substrates.
A rapid, continuous spectrophotometric assay for measuring the amount and activity of several lipolytic enzymes is described. It is based on the metachromatic properties of the cationic dye safranine, and makes use of the fact that an adequate combination of a lipolytic enzyme with one of its substrates leads to a change in the net negative charge at the lipid/water interface, which is monitored by the absorbance change of safranine. Utilizing this method, most lipolytic enzymes can be detected in very low amounts (milliunit or less) in about 1 min without employing radiolabelled lipids or synthetic lipid analogues. Over a wide range of enzyme concentrations, there is a good linearity between the initial hydrolysis rate (determination by the safranine method) and the amount of enzyme. The versatility of the assay is illustrated by examples showing how phospholipase A2, triacylglycerol hydrolase, phospholipase D or phospholipase C (either general or phosphatidylinositol-specific) activities can be detected, either separately or sequentially. Due to its high sensitivity, simplicity, and rapidity, this assay should find its main application in monitoring column effluents during the purification steps of lipolytic enzymes.
Rawyler
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Laboratoire de Physiologie végétale, Université de Neuchâtel, Switzerland.
Siegenthaler
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PA
D000818:Animals; D002265:Carboxylic Ester Hydrolases / Q000378:metabolism*; D004396:Coloring Agents; D004563:Electrochemistry; D006868:Hydrolysis; D007700:Kinetics; D008049:Lipase / Q000378:metabolism; D008066:Lipolysis; D010619:Phenazines; D043265:Phosphatidylinositol Diacylglycerol-Lyase; D010739:Phospholipase D / Q000378:metabolism; D010741:Phospholipases A / Q000378:metabolism; D054467:Phospholipases A2; D010727:Phosphoric Diester Hydrolases / Q000378:metabolism; D013053:Spectrophotometry; D010738:Type C Phospholipases / Q000378:metabolism
D004396:Coloring Agents; D010619:Phenazines; D002265:Carboxylic Ester Hydrolases; D008049:Lipase; D010741:Phospholipases A; D054467:Phospholipases A2; D010727:Phosphoric Diester Hydrolases; D010738:Type C Phospholipases; D010739:Phospholipase D; D043265:Phosphatidylinositol Diacylglycerol-Lyase; C009195:safranine T