The equilibrium constant for the reaction is related to ΔG°  by the relation:
where T is the absolute temperature and R is the gas constant.  A positive value of ΔG° therefore implies
so that starting from molar stoichiometric quantities such a reaction would move backwards toward equilibrium, not forwards.
Nevertheless, endergonic reactions are quite common in nature, especially in biochemistry and physiology. Examples of endergonic reactions in cells include protein synthesis, and the Na/K pump which drives nerve conduction and muscle contraction.