Noun
pupylation (uncountable) (Also: PUPylation)
(biochemistry) The conjugation of the PUP protein to the amino groups of lysine amino acids in target proteins
In contrast to the three-step reaction of ubiquitination, pupylation requires two steps, therefore only two enzymes are involved in pupylation. Source: Internet
Prokaryotic ubiquitin-like protein (Pup) serves the same function (targeting proteins for degradations), although the enzymology of ubiquitination and pupylation is different. Source: Internet