<unk>  (LepA) is an elongation factor that is thought to back-translocate on the ribosome during the translation of RNA to proteins in all prokaryotes and eukaryotes that have maintained functioning mitochondria.  There are three primary elongation factors (EF-G, EF-Tu, EF-Ts) that are known to be the main contributors to facilitate elongation during protein synthesis; due to LepA's now acknowledged proofreading function in translation, scientists are now lobbying to have LepA renamed as EF-4 (elongation factor 4).
Leader peptidase A
Clostridiopeptidase
Glycoprotein 2-beta-D-xylosyltransferase
Diastase
Pegaspargase
Agalsidase beta
Xylosylprotein 4-beta-galactosyltransferase 
Saruplase