Taurine Depletion in the Intact Animal Stimulatesin vitroPhosphorylation of an 44-kDa Protein Present in the Mitochondrial Fraction of the Rat Heart

Sprague–Dawley rats were treated with 1.5% guanidinoethanesulfonic (GES) acid in their water in order to deplete the taurine levels partially in cardiac tissue. After 6 weeks of GES treatment,in vitrophosphorylation of a 44 kDa protein present in the mitochondrial fraction of the rat heart was increased by 85%. The increase in thein vitrophosphorylation of the specific 44 kDa protein after GES treatment was reversed when the animals were subsequently given 1.5% taurine in their drinking water for an additional 6 weeks. Taurine (1.5%) alone for a period of 6 weeks had no effect on the phosphorylation of the 44 kDa protein. These results suggest that taurine has a regulatory role in the phosphorylation of a specific protein in cardiac tissue.