Skip to main content
. 2007 Sep 7;189(21):7697–7708. doi: 10.1128/JB.01090-07

FIG. 9.

FIG. 9.

UV visible and mass spectra of norcobalamin and UNK2. Shown are the UV-visible spectrum (A and B) and matrix-assisted laser desorption ionization-time of flight mass spectrum (C and D) of HPLC-purified cobamides. The absorption spectrum of the corrinoid eluting at 28.3 min postinjection (A) is identical to that of authentic cyanocobalamin. The signals with m/z values of 1,315.6 and 1,353.6 a.m.u. (C) were consistent with (M − 1)+, and (M − 1 + K+)+ ions of norcobalamin, respectively. The signals with m/z values of 1,331.7 and 1,369.6 a.m.u. (D) suggest this cobamide of unknown identity could be norpseudovitamin B12 (M + 1)+ and deprotonated norpseudovitamin B12 plus a K+ ion (M − 1 + K+)+. Further tests need to be performed to determine the identity of cobamide UNK2.