TURBIDIMETRIC ASSAY FOR PHOSPHOLIPASE A.

concentrations of albumin augmented enzymatic activity, whereas high concentrations inhibited it. Certain ions (example: Hg++) shortened or completely abolished an initi,al lag period; other ions (example: Ca++) inhibited enzymatic activity. EDTA ikhibited activity, apparently becazwe it formed a complex with a component of the substrate system, probably the deoxyoholate. A high correlation was obtained between the turbidimetric and titrimet~ric measures of phospholipase activity. I n recent years, turbidimetric methods have been used by various workers for estimating activity of lipase,l, 2, 3 clearing faetor,4s 5 and phospholipase C of bacterial origin.‘jt 7 The advantages of these turbidimetric methods are their simplicity, speed, and generally smaller requirement for substrate. Saunders8 reported that pure lecithin sols were stable for long periods, although turbid in appearance, and that this turbidity was reduced by the

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