AND OTHERS

During 1949 we isolated three red crystalline antipernicious anaemia factors from Streptomyce8 griseus fermentation liquors. The first of these was vitamin B12 itself, originally isolated by Rickes, Brink, Koniuszy, Wood & Folkers (1948) and a little later in these laboratories (Lester Smith & Parker, 1948). The next was vitamin Bl2b, the second factor we obtained from liver; it was later crystallized by Pierce, Page, Stokstad & Jukes (1949). The third was vitamin B120, which has been referred to under its temporary designation 'vitamin B12.' at scientific meetings (Lester Smith, Ungley, Mollin & Dacie, 1950; Buchanan, Johnson, Mills & Todd, 1950a, b; Anslowetal. 1950; Lester Smith etal. 1951). These were all obtained by methods of isolation unlikely to alter the factors chemically. In addition, however, we have obtained anumber ofother closely related factors by mild chemical treatments ofthese B12 vitamins (Lester Smith, Ball & Ireland, 1952). On hydrolysis with 5N-HCl followed by shaking with n-octanol, vitamins B1, and B120 gave red esters with identical absorption spectra, indicating that a major portion of the molecule is common to both (Fantes & Ireland, 1950).