Cobalamin

Cobalamin with the upper axial ligand noted as R

Cobalamin may refer to several chemical forms of vitamin B₁₂, depending on the upper axial ligand of the cobalt ion. These are:

Cyanocobalamin (R = –CN)
Hydroxocobalamin (R = –OH)
Methylcobalamin (R = –CH₃), an active form of vitamin B₁₂
Adenosylcobalamin (R = –Ado), also an active form of vitamin B₁₂

Cobalamin is susceptible to acid. During its biosynthesis, complexes are formed which protect it.

Types of tetrapyrroles

Bilanes
(Linear)

Phytobilins

Phytochromobilin

Phycobilins	Phycoerythrobilin Phycocyanobilin Phycourobilin Phycoviolobilin

Macrocycle

Corrinoids

Porphyrins

Protoporphyrins	Protoporphyrin IX Heme (b, c, a, o) Zinc protoporphyrin Magnesium protoporphyrin

Phytoporphyrins	Chlorophyll c Protochlorophyllide

Reduced
porphyrins

Porphyrinogens	Uroporphyrinogen (I, III) Coproporphyrinogen (I, III) Protoporphyrinogen IX

Chlorins	Chlorophyllide (a, b) Chlorophyll (a, b) Phaeophytin (a, b) Bacteriochlorophyll c

Bacteriochlorins	Bacteriochlorophyll a

Isobacteriochlorins	Siroheme Sirohydrochlorin

Corphins	Cofactor F430

Authority control	NDL: 00566071

This article is issued from Wikipedia - version of the Monday, October 19, 2015. The text is available under the Creative Commons Attribution/Share Alike but additional terms may apply for the media files.