  In this paper we summarize some results of our theoretical investigations of
helix-coil transition both in single-strand (polypeptides) and two-strand
(polynucleotides) macromolecules. The Hamiltonian does not contain any
parameter designed especially for helix-coil transition and uses pure molecular
microscopic parameters. To calculate averages we evaluate the partition
function using transfer-matrix approach. The GMPC allowed to describe the
influence of a number of factors, affecting the transition, basing on a unified
microscopic approach. Thus we obtained, that solvents change transition
temperature and interval in different ways, depending on type of solvent and on
energy of solvent-macromolecule interaction; stacking on the background of
H-bonding increases stability and decreases cooperativity of melting. For
heterogeneous DNA we could analytically derive well known formulae for
transition temperature and interval. In the framework of GMPC we calculate and
show the difference of two order parameters of helix-coil transition - the
helicity degree, and the average fraction of repeated units in helical
conformation.
