A novel enzyme, tagatose kinase, from Mycobacterium butyricum.

A novel enzyme catalyzing the phosphorylation of D-tagatose to D-tagatose 6-phosphate with ATP has been identified in extracts of dulcitol-grown Mycobacterium butyricum. The enzyme was purified 100-fold with 29% recovery. It required Mg2+, Mn2+ or Fe2+ and showed maximum activity at pH 7.5. The molecular weight as determined by Sephadex G-100 filtration amounted to 63 000. The apparent Michaelis constants for D-tagatose and ATP were 0.8 and 1.0 mM, respectively. The enzyme preparations were not very sensitive to SH group inhibitors and heavy metals but rapidly lost activity on heating above 50 degrees C.