Use of thiaminase I in the determination of thiamine in biological materials

Abstract

The usefulness of thiaminase I enzyme in preparing “thiamine-free” blanks for the determination of non-thiochrome fluorescence in thiamine determinations has been evaluated. The level of thiaminase I has been optimised and an improved thiochrome procedure for the assay of thiamine developed. The modified procedure involves the direct measurement of thiamine in crude extracts and thus is much simpler and more rapid than other procedures that involve ion-exchange purification of the thiamine. Unlike the chemical procedures used for the preparation of thiamine-free blanks, thiaminase I is highly specific.