N-terminal sequence of an encephalitogenic protein form human myelin.

Experimental allergic encephalomyelitis is produced by injection of a basic protein from centralnervous tissue mixed with Freund's complete adjuvant into guinea pigs (Kies, 1965; Carnegie, Bencina & Lamoureux, 1967). The encephalitogenic basic protein is a component of myelin (Laatsch, Kies, Gordon & Alvord, 1962; Roboz-Einstein, Csejtey & Davis, 1965; Eng, Chao, Gerstl, Pratt & Tavaststjerna, 1968). Huuman brain was defatted with chloroformmethanol (2:1, v/v) and the encephalitogenic protein extracted at pH2-5-3-0. The basic proteins were collected on CM-Sephadex C-25 and eluted with 081N-HCI. Gel filtration on Sephadex G-100, G-75 and G-50 was used to purify the encephalitogenic protein. In calculating the amino acid composition shown in Table 1 the protein was assumed to contain six histidine residues, since six histidyl peptides were observed in a peptide 'map' of a tryptic digest. The values for serine, threonine and tyrosine are extrapolated to zero time of hydrolysis with constant-boiling HCI. Tryptophan