Editing Proteinoid (section)

{{Refimprove|date=December 2009}}
'''Proteinoids''', or '''thermal proteins''', are [[protein]]-like, often cross-linked molecules formed abiotically from [[amino acid]]s.<ref name='Fox 1997'>{{cite book | vauthors = Fox SW, Klaus D |author-link1=Sidney_W._Fox |title=Molecular Evolution and the Origin of Life |year=1977 |publisher=W. H. Freeman & Co Ltd |isbn=978-0-7167-0163-7 }}</ref> [[Sidney W. Fox]] initially proposed that they may have been precursors to the first [[life|living]] [[cell (biology)|cells]] ([[protocell|protocells]]).<ref name="Fox 1997" /> The term was also used in the 1960s to describe peptides that are shorter than twenty amino acids found in hydrolysed protein,<ref>{{cite journal | vauthors = Hayakawa T, Windsor CR, Fox SW | title = Copolymerization of the Leuchs anhydrides of the eighteen amino acids common to protein | journal = Archives of Biochemistry and Biophysics | volume = 118 | issue = 2 | pages = 265–272 | date = February 1967 | pmid = 6033704 | doi = 10.1016/0003-9861(67)90347-5 | hdl-access = free | hdl = 2060/19660025877 }}</ref> but this term is no longer commonly used.<ref name="Fox 1997" />