The members of this family are similar to the hypothetical protein yhhN expressed by E. coli (Swiss:P37616). Many are annotated as possible transmembrane proteins, and in fact they all have a high proportion of hydrophobic residues. A human member of this family, formerly known as TMEM86B, is a lysoplasmalogenase that catalyzes the hydrolysis of the vinyl ether bond of lysoplasmalogen[1]. Putative conserved active site residues have been proposed for the YhhN family [2].

1: Purification, identification, and cloning of lysoplasmalogenase, the enzyme that catalyzes hydrolysis of the vinyl ether bond of lysoplasmalogen. Wu LC, Pfeiffer DR, Calhoon EA, Madiai F, Marcucci G, Liu S, Jurkowitz MS; J Biol Chem. 2011;286:24916-24930. PMID:21515882

2: Large-scale determination of previously unsolved protein structures using evolutionary information. Ovchinnikov S, Kinch L, Park H, Liao Y, Pei J, Kim DE, Kamisetty H, Grishin NV, Baker D; Elife. 2015; [Epub ahead of print] PMID:26335199