Physical and structural properties of taurine and taurine analogues

Abstract

In a variety of mammalian species it has been established that taurine is a necessary component of the visual system, however, the exact mechanism(s) as to the function of taurine is(are) elusive. Additionally, taurine is speculated to be a membrane stabilizer by interacting with phospholipids and a regulator of protein phosphorylation. Therefore the inhibition by taurine and taurine analogues of the phosphorylation of an ≈20 kDa protein present in the mitochondrial fraction of the rat retina has been investigated using computational methods. Correlations between molecular weight, molecular volume, and calculated pKa values vs. IC50 values are reported. These data appear to support the hypotheses according to Lombardini and Props that the inhibition of the phosphorylation of an ≈20kDa protein by taurine and taurine analogues is dependent on (i) the critical distance between the nitrogen and sulfur atoms in the taurine moiety (S-C-C-N) of the analogue; (ii) the environment of the nitrogen atom in the taurine analogue (saturated ring vs. unsaturated ring); and (iii) the placement of both the sulfur and nitrogen atoms not being present simultaneously in the ring structure. Using computational methods we present results that support hypotheses (i) and (ii).