CHPF

CHPF encodes a chondroitin polymerizing factor, which is involved in the biosynthesis of chondroitin sulfate. Chondroitin sulfate is a repeating disaccharide structure of (GalNAcβ1,4GlcAβ1,3). CHPF is thought to forms a complex with CHSY1, CSGlcAT, and CHPF2 to elongate the chondroitin chain. CHPF alone has little enzymatic activity, but when expressed with CHSY, it shows high chondroitin elongation activity (both GalNAc-transferase activity and GlcA-transferase activity). Another paper also reported that CHPF alone shows weak GalNAc-transferase and GlcA-transferase activities.