Enzymic assay of creatinine in serum and urine with creatinine iminohydrolase and glutamate dehydrogenase.

We describe an assay for creatinine in which it is converted by creatinine iminohydrolase (EC 3.5.4.

Improved method for determination of high-density-lipoprotein cholesterol II. Enzymic determination of cholesterol in high-density lipoprotein fractions with a sensitive reagent.

A reagent is described for the colorimetric enzymic determination of high-density-lipoprotein (HDL) cholesterol. The reagent can be used with HDL fractions isolated by the various methods of precipitation of low- and very-low-density lipoproteins we investigated. The considerable sensitivity obtained by use of Barham-Trinder's reaction allows the sample/reagent volume ratio to be decreased to 1:80, and major interferences thus eliminated.

Improved method for determination of high-density-lipoprotein cholesterol I. Isolation of high-density lipoproteins by use of polyethylene glycol 6000.

We describe a modified method of precipitating low- and very-low-density lipoproteins with polyethylene glycol, for quantitation of high-density lipoprotein cholesterol. A 100 g/L concentration of polyethylene glycol 6000 in a buffered (pH 10) solution is used. Under these conditions precipitation of beta-lipoproteins is complete.

Immobilized enzymes in continuous-flow analysis.

Glucose oxidase, uricase, and urease were immobilized on the interior surface of activated polyamide tubing. The shelf-life of such enzyme bearing tubes was at least six months. The tubes were used for continuous-flow analysis of glucose, uric acid, and urea with conventional systems and with hybrid micro-scale systems in which modules of different manufacture were combined.