|Jmol-3D images||Image 1|
|Molar mass||118.09 g mol−1|
|Acidity (pKa)||pKa1 = 3,07
pKa2 = 5,76
|Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)|
|(what is: / ?)|
The coenzyme A linked form of methylmalonic acid, methylmalonyl-CoA, is converted into succinyl-CoA by methylmalonyl-CoA mutase, in a reaction that requires vitamin B12 as a cofactor. In this way, it enters the Krebs cycle, and is thus part of one of the anaplerotic reactions.
Increased methylmalonic acid levels may indicate a vitamin B12 deficiency. However, it is sensitive (those with the disease almost always test positive) but not specific (those that test positive do not always have the disease). MMA is elevated in 90-98% of patients with B12 deficiency. It has lower specificity as 20-25% of patients over the age of 70 have elevated levels of MMA, but 25-33% of them do not have B12 deficiency. For this reason, MMA test is not routinely recommended in the elderly.
An excess is associated with methylmalonic acidemia.