Partial purification and characterization of monomethylethanolamine kinase and dimethylethanolamine kinase activities from rat liver.

Monomethylethanolamine (MEA) kinase and dimethylethanolamine (DEA) kinase activities were purified 950 and 750 fold respectively from rat liver by conventional procedures. Certain properties of the partially purified enzyme preparation suggest that they are different from both choline kinase activity and ethanolamine kinase activity and differ from one another. This is based upon the following observations: 1. The heat stabilities of MEA kinase and DEA kinase activities are significantly different from one another and are different from the stability of choline kinase and ethanolamine kinase activities. 2. K+ in the presence of Mg2+ increases MEA kinase activity by 100% but has no effect on DEA kinase activity. 3. Different Ki values and the types of inhibition by several structurally related amino alcohols were found for MEA kinase and DEA kinase activities. 4. The purification fold of MEA kinase and DEA kinase are different from each other and from that of choline kinase and ethanolamine kinase.