Vitamin B 12, also known as cobalt amine, is the only vitamin containing metal elements. In nature, vitamin B12 is synthesized by microorganisms. Higher animals and plants cannot make vitamin B12. Vitamin B12 is the only vitamin that requires the help of an intestinal secretion (endogenous factor) to be absorbed. Some people due to gastrointestinal abnormalities, lack of this endogenous factor, even if adequate dietary sources can also suffer from malignant anemia. There is basically no vitamin B12 in vegetable foods. It stays in the gut for a long time and takes about three hours (most water-soluble vitamins take only a few seconds) to be absorbed. Vitamin B 12's main physiological function is to participate in the production of bone marrow red blood cells, prevent malignant anemia, prevent brain nerve damage. Vitamin B 12 is one of the last B vitamins to be found so far. Vitamin B12 is a polycyclic compound containing 3 valent cobalt. Four reduced pyrrole rings are linked together to form a Golin macroring (similar to porphyrin), which is the core of vitamin B12 molecule. Therefore, compounds containing this ring are referred to as Golin-like. Vitamin B12 is a light red acicular crystal which is easily soluble in water and ethanol. It is most stable under the condition of weak acid pH 4.5 and 5.0, and decomposes in strong acid (pH < 2) or alkaline solution, which can be destroyed to some extent in the event of heat. But short time high temperature disinfection loss is small, encounter bright light or ultraviolet ray is easy to be destroyed. The loss of ordinary cooking process is about 30%.

Enw Cynnyrch:	VITAMIN 12
CAS:	68-19-9
MF:	C63H88CoN14O14P
MW:	1355.37
EINECS:	200-680-0
Mae fitamin B12, a elwir yn VB12 yn fyr, a elwir hefyd yn cobalamin, ac mae'n un o'r fitaminau B, yn ddosbarth o gyfansoddion organig cymhleth sy'n cynnwys dosbarth Corrin cobalt, ac roedd yn cynnwys cobalt trivalent mewn awyren porphyrin Corrin tebyg yng nghanol y cylch. . Dyma'r moleciwl fitamin mwyaf a mwyaf cymhleth sydd wedi'i ddarganfod. Dyma hefyd yr unig fitamin ag ïon metel. Mae'r grisial yn goch, fe'i gelwir hefyd yn fitamin coch. Nid yw'r planhigyn yn cynnwys VB12, ac ni all gynhyrchu VB12. Yr afu yw ffynhonnell orau VB12, yna o laeth, cig, wyau, pysgod ac ati. Mae VB12 yn coenzyme hanfodol wrth synthesis RNA a DNA. Gall diffyg VB12 in vivo achosi newidiadau patholegol yn y system nerfol fel nerf ymylol a'r system nerfol ganolog.