original_query: What is the function of OGT enzyme?
query: What is the function of OGT enzyme?
answer: OGT (O-GlcNAc transferase) catalyzes the addition of a single N-acetylglucosamine to serine or threonine residues (and cysteine residues) of nucleocytoplasmic proteins.  It's involved in a host of biological functions, including insulin resistance, embryogenesis, intracellular glycosylation, and modification of transcription factors and RNA polymerase II.  It also cleaves Host Cell Factor C1.