Vitamins, Harmones and Hemoglobin
Which one of the following statements conce-rning vitamin B12 is correct?
|A||The cofactor form is vitamin B12 itself.|
|B||It is involved in the transfer of amino groups.|
|C||It requires a specific glycoprotein for its absorption.|
|D||It is present in plant products.|
a. Vitamin B12 requires intrinsic factor for its absorption. A deficiency of vitamin B12 is most often caused by a lack of intrinsic factor.
b. However, high does of the vitamin, given orally, are sufficiently absorbed to serve as treatment for pernicious anemia.
c. The cofactor forms are methylcobalamin and deoxyadenosylcobalamin. Vitamin B6, not vitamin B12, is involved in the transfer of amino groups. B12 is found in food derived from animal sources.