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 fractio n of them were present in the alpha(2)beta(2) tetramer, while coexpression with type III procollagen markedly increased their assembly level. We repor t here that the half-life of the recombinant 4-PH tetramer in Pichia when s tudied by pulse-chase experiments was only 50 min. Coexpression with the pr oal(III) chains increased this half-life to 12.5 h. Coexpression with the p ro alpha 1(I) chains, which were produced at half the level of the proal(II I) chains, gave a half-life of 6.5 h. Coexpression with collagen thus marke dly increases the half-life of the 4-PH tetramer, and the half-life may be related to the level of collagen expression. (C) 1999 Published by Elsevier Science B.V./International Society of Matrix Biology. All rights reserved.