Functional heterogeneity of transducin α subunits

Abstract
The N‐terminal glycine of transducin α subunits is acylated by lauroyl (C12:0), myristoyl (C14:0), (cis‐Δ5)‐tetradecaenoyl (C14:1) or (cis,cis‐Δ58)‐tetradecadienoyl (C14:2) fatty acyl groups. We examined functional heterogeneity of transducin by sequentially eluting it from bleached outer segments using increasing concentrations of GTP then identifying the N‐terminal acyl groups on the eluted α subunits. C14:2 acylated transducin eluted at low GTP concentrations followed by C12:0, C14:1 and C14:0 transducin at higher GTP concentrations. This suggests functional heterogeneity in the different forms of transducin α subunits.