Cereal Chem 49:544 - 553.  |  VIEW ARTICLE
Automated Method for the Determination of D-Glucose-Isomerase Activity.

N. E. Lloyd, K. Khaleeluddin, and W. R. Lamm. Copyright 1972 by the American Association of Cereal Chemists, Inc. 

An automated procedure for the determination of the glucose-isomerase activity of extracts of microorganisms is described. Activities of whole cells and sonicates of whole cells can also be determined, provided they are sufficiently well dispersed. In the procedure, the sample is incubated with buffered D- glucose solution, and the fructose produced is determined colorimetrically with cysteine-carbazole-sulfuric acid reagent by Technicon Auto-Analyzer equipment. Samples are analyzed in pairs, and one sample of the pair provides a blank to correct for substances which may interfere with the colorimetric fructose determination. The standard deviation of single determinations is +/-2.5% relative. The preparation of a stable glucose-isomerase standard used for calibration of the automated procedure is also described.