Endoplasmic reticulum 2-OH acyl-CoA lyase involved in the cleavage (C1 removal) reaction in the fatty acid alpha-oxydation in a thiamine pyrophosphate (TPP)-dependent manner. 2-hydroxyoctadecanoyl-CoA = formyl-CoA + heptadecanal (2R)-hydroxyhexadecanoyl-CoA = formyl-CoA + pentadecanal Binds 1 Mg(2+) ion per subunit. Binds 1 thiamine pyrophosphate per subunit. Belongs to the TPP enzyme family.