We solve a functional
version of the problem of twist quantization of a coboundary Lie bialgebra (g,r,Z).
We derive from this that the formal Poisson manifolds g∗ and G∗ are isomorphic, and
we construct an injective algebra morphism S(g∗)g↪U(g∗). When (g,r,Z) can be
quantized, we construct a deformation of this morphism. In the particular case when
g is quasitriangular and nondegenerate, we compare our construction with
Semenov-Tian-Shansky’s construction of a commutative subalgebra of U(g∗).
We also show that the canonical derivation of the function ring of G∗ is
Hamiltonian.