cytidine monophosphate-N-acetylneuraminic acid hydroxylase-like; CMP-NeuAc hydroxylase-like protein (CMAH, CMAHP)

Function

• unknown
• has no CMP-N-acetylneuraminic acid hydroxylase activity

Structure

• belongs to the CMP-Neu5Ac hydroxylase family
• contains 1 Rieske domain

Alternative splicing

named isoforms=3

Expression

• widely expressed
• highly expressed in thymus
• not expressed in brain

Evolution

• although related to CMP-Neu5Ac hydroxylase, lacks the catalytic N-terminal domain
• this explains the absence CMP-Neu5Gc sialic acid in human, while it is abundantly expressed at the surface of many cells in other vertebrates
• inactivation is due to an Alu-mediated inactivating mutation of gene in common ancestors of humans & Neanderthals approximately 2.1-2.2 million years ago, before brain expansion

Notes

• may be the product of a pseudogene

More general terms

• evolutionary divergent human protein

Database

• OMIM: https://mirror.omim.org/entry/603209
• UniProt: http://www.uniprot.org/uniprot/Q9Y471.html