Coexpression with collagen markedly increases the half-life of the recombinant human prolyl 4-hydroxylase tetramer in the yeast Pichia pastoris.

Recent coexpression studies of the subunits of human prolyl 4-hydroxylase (4-PH) in the yeast Pichia pastoris have indicated that only a minor fraction of them were present in the alpha2beta2 tetramer, while coexpression with type III procollagen markedly increased their assembly level. We report here that the half-life of the recombinant 4-PH tetramer in Pichia when studied by pulse-chase experiments was only 50 min. Coexpression with the pro alpha1(III) chains increased this half-life to 12.5 h. Coexpression with the pro alpha1(I) chains, which were produced at half the level of the pro alpha1(III) chains, gave a half-life of 6.5 h. Coexpression with collagen thus markedly increases the half-life of the 4-PH tetramer, and the half-life may be related to the level of collagen expression.