Abstract: New substrates for .gamma.-glutamyltransferase (.gamma.-GT) are disclosed. These subtrates are useful in the colorimetric determination of .gamma.-GT since the cleavage of the .gamma.-glutamyl group produces a detectable species--an aminostyrylquinolinium dye. The substrates have the formula: ##STR1## wherein: R and R.sub.1 are independently selected from hydrogen, alkyl and alkoxy andQ is ##STR2## wherein: R.sub.2 is alkyl having from 1 to 4 carbon atoms;R.sub.3 and R.sub.4 are independently selected from hydrogen, alkyl, alkoxy, nitro, cyano and halogen; andX.sup..crclbar. is an anion.

Abstract: A method for the purification and recovery of cholesterol oxidase is disclosed. Cholesterol oxidase is purified by a method including the steps of:(a) contacting a solution of the cholesterol oxidase to be purified with a chromatography composition comprising an unbound water-insoluble steroid which is a nonsubstrate for cholesterol oxidase so as to adsorb the cholesterol oxidase on the steroid;(b) separating the solution from the steroid; and(c) contacting the steroid with an eluting solution containing a surfactant at a concentration between 0.001 percent and 10 percent so as to recover the adsorbed cholesterol oxidase.In a preferred embodiment, the solution containing the cholesterol oxidase to be purified is a microorganism growth medium having cholesterol oxidase activity and, prior to the step of contacting the solution with a steroid, the solution is contacted with an ion-exchange chromatography material.

Abstract: A composition and element for assaying a neuraminic acid comprises a neuraminic acid aldolase, pyruvate oxidase and an electron acceptor. A sample containing a neuraminic acid can be contacted with the composition and the product detected spectrophotometrically.

Abstract: An integral analytical element for analysis of liquids for their cholesterol content is disclosed. The element is of the type which comprises at least two superposed layers including a spreading layer and a reagent layer in fluid contact and, optionally, a support. Cholesterol oxidase and a composition for the hydrolysis of cholesterol esters comprising lipase having cholesterol esterase activity and protease are included in the element such that cholesterol esters contained in a sample applied to the spreading layer are saponified to free cholesterol and free cholesterol is decomposed in the presence of cholesterol oxidase to produce a detectable change related to the total cholesterol content of the sample.