Editing Gerald Edelman (section)

===Antibody sequencing===
Edelman and his colleagues used [[Cyanogen bromide#Protein cleavage|cyanogen bromide]] and [[protease]]s to fragment the antibody protein subunits into smaller pieces that could be analyzed for determination of their [[Protein sequencing|amino acid sequence]].<ref>{{Cite journal
| pmid = 5650389
| year = 1968
| last1 = Cummingham | first1 = B.
| last2 = Gottlieb | first2 = P.
| last3 = Konigsberg | first3 = W.
| last4 = Edelman | first4 = G.
| title = The covalent structure of a human gamma G-immunoglobulin. V. Partial amino acid sequence of the light chain
| volume = 7
| issue = 5
| pages = 1983–1994
| journal = Biochemistry
| doi = 10.1021/bi00845a049
}}</ref><ref>{{Cite journal
| pmid = 4177258
| year = 1968
| last1 = Gottlieb | first1 = P. D.
| last2 = Cunningham | first2 = B. A.
| last3 = Waxdal | first3 = M. J.
| last4 = Konigsberg | first4 = W. H.
| last5 = Edelman | first5 = G. M.
| title = Variable regions of heavy and light polypeptide chains of the same gammaG-immunoglobulin molecule
| volume = 61
| issue = 1
| pages = 168–175
| pmc = 285919
| journal = Proceedings of the National Academy of Sciences of the United States of America
| doi = 10.1073/pnas.61.1.168
|bibcode = 1968PNAS...61..168G | doi-access = free
}}</ref> At the time when the first complete antibody sequence was determined (1969)<ref>{{Cite journal
| pmid = 5257969
| year = 1969
| last1 = Edelman | first1 = G. M.
| last2 = Cunningham | first2 = B. A.
| last3 = Gall | first3 = W. E.
| last4 = Gottlieb | first4 = P. D.
| last5 = Rutishauser | first5 = U.
| last6 = Waxdal | first6 = M. J.
| title = The covalent structure of an entire gammaG immunoglobulin molecule
| volume = 63
| issue = 1
| pages = 78–85
| pmc = 534037
| journal = Proceedings of the National Academy of Sciences of the United States of America
| doi = 10.1073/pnas.63.1.78
|bibcode = 1969PNAS...63...78E | doi-access = free
}}</ref> it was the largest complete protein sequence that had ever been determined. The availability of amino acid sequences of antibody proteins allowed recognition of the fact that the body can produce many different antibody proteins with similar antibody constant regions and divergent antibody [[variable region]]s.