bifunctional protein NCOAT; meningioma-expressed antigen 5; nuclear cytoplasmic O-GlcNAcase & acetyltransferase; includes: protein O-GlcNAcase; glycoside hydrolase O-GlcNAcase; hexosaminidase C; N-acetyl-beta-D-glucosaminidase; N-acetyl-beta-glucosaminidase; O-GlcNAcase; OGA; includes: histone acetyltransferase; HAT (MGEA5, HEXC, KIAA0679, MEA5)

Function

• hydrolysis of terminal non-reducing N-acetyl-D-hexosamine residues in N-acetyl-beta-D-hexosaminides
• cleaves GlcNAc but not GalNAc from glycopeptides
• can use p-nitrophenyl-beta-GlcNAc as substrate but not p-nitrophenyl-beta-GalNAc or p-nitrophenyl-alpha-GlcNAc
• possesses hyaluronidase activity
• acetylates Lys-8 of histone H4 & Lys-14 of histone H3
• binds both acetylated & unacetylated histone H4 tail
  • acetylation on Lys-8 of histone H4 abolishes binding
• inhibited by N-acetylglucosamine, but not N-acetylgalactosamine
• proteolytically cleaved by caspase-3

Kinetic parameters:

• KM=1.1 mM for pNP-GLcNAc
• Vmax=652 umol/min/mg enzyme with pNP-GLcNAc as substrate
• Optimum pH is 5.7-7

Structure

monomer

Compartment

• isoform 1: cytoplasm
• isoform 3: nucleus

Alternative splicing

named isoforms=3

Expression

• ubiquitous
• highest expression in brain, placenta, pancreas

More general terms

• enzyme
• phosphoprotein

Additional terms

• beta N-acetylhexosaminidase
• histone acetyltransferase

Database

• Entrez gene: http://www.ncbi.nlm.nih.gov/sites/entrez?db=gene&cmd=Retrieve&dopt=Graphics&list_uids=10724
• Kegg: http://www.genome.jp/dbget-bin/www_bget?hsa:10724
• OMIM: https://mirror.omim.org/entry/604039
• UniProt: http://www.uniprot.org/uniprot/O60502.html