Herstellung hochgereinigtermyo-Inosit-1-phosphat-Synthase aus stierhoden und Vergleich mit dem entsprechenden Enzym aus Rattenhoden

Using the method of affinity chromatography on NAD-Sepharose, themyo-inositol-1-phosphate synthase (EC 5.5.1.4) from testicles of the bull could be purified to homogeneity. Although its specificity, its activity and its molecular weight are all very similar to the corresponding properties of the enzyme from rat testicles, there are also some considerable differences between the two enzyme proteins. Whereas the rat enzyme consists of two different pairs of subunits with the molecular weights of 3.5×10⁴ and 7.2×10⁴, respectively, the bull enzyme consists of four subunits, all of them apparently having the same molecular weight of 5.45×10⁴. The isoelectric points of the two enzyme proteins are also different; with the help of the method of isoelectric focussing they were determined as 3.95 for the rat enzyme and 4.59 for the enzyme from the bull.