Nitritocobalamin and nitrosocobalamin may be confused with sulfitocobalamin using cation-exchange chromatography.
The previously reported ability of SP-Sephadex C25 column chromatography for partitioning biologically important cobalamins has been modified to include analytical separation of nitritocobalamin (NO2-Cbl) and nitrosocobalamin (NO-Cbl). Gel column dimensions (1.5 x 11.0 cm), a low eluent flow-rate (125 microliters/min), collection of small eluate fractions (160 microliters) plus maintenance of He saturated mobile and gel phases all combined to eliminate ordinarily confusing proximal elution of NO2-Cbl and NO-Cb1 with sulfitocobalamin (SO3-Cbl) and cyanocobalamin. Cobalamin elution profiles from the gel column were monitored by direct radiometric analysis of 57Co-labelled cobalamin standards or competitive intrinsic factor radioassays for cobalamin sample sizes up to 10.0 ng. Failure to implement the chromatographic conditions detailed here totally obscured analysis of NO2-Cbl coexisting with SO3-Cbl in brain tissues for chicks exposed to dietary sulfites and caused oversight of NO-Cb1 normally coexisting in prepared NO2-Cbl standards.
Framingham Institute for Food Science, Technology and Nutritional Biochemistry, Framingham State College, MA 01701.
J M
JM
Anes
R A
RA
Beck
J J
JJ
Brink
R J
RJ
Goldberg
D000818:Animals; D001923:Brain Chemistry; D002645:Chickens; D002852:Chromatography, Ion Exchange; D003037:Cobalt Radioisotopes / Q000032:analysis; D004032:Diet; D006879:Hydroxocobalamin / Q000031:analogs & derivatives* / Q000302:isolation & purification; D008297:Male; D009603:Nitroso Compounds / Q000302:isolation & purification*; D011865:Radioisotope Dilution Technique; D013447:Sulfites / Q000493:pharmacokinetics; D014805:Vitamin B 12 / Q000031:analogs & derivatives* / Q000302:isolation & purification*
D003037:Cobalt Radioisotopes; D009603:Nitroso Compounds; D013447:Sulfites; C079584:nitrosocobalamin; C016763:sulfitocobalamin; C092105:nitritocobalamin; D014805:Vitamin B 12; D006879:Hydroxocobalamin