Ionic calcium: Calcium absorption is closely related to blood levels of ionic calcium. It is locally regulated by the active form of Vitamn D, which promotes active calcium absorption. pg 900 Anatomy Book
Calcium is locally regulated in the blood. This regulation is enacted by vitamin D, which acts as a cofactor to the calcium.
calcium
the general term is cofactor, but more specifically, if the cofactor is an organic molecule, it is called a coenzyme
Mg2+ is a cofactor of the enzyme peroxidase. In order to keep the enzyme active, this cofactor must be supplied. Magnesium chloride dissociates in solution into magnesium and chloride ions. The cofactor requirement is thus met
cofactor necessary for enzyme activity
Supplements may contain either the active or precursor forms of vitamin A. The active form may be more desirable for those who may have some difficulty in converting the carotenoids into the active vitamin.
The bonds that hold the the substrate to the active site are hydrogen bonds. These are relatively weak bonds.
French Fries.
Calcitriol
The sodium potassium pump is an example of active transport. Enzymatic reactions can be affected by pH, salinity, temperature, and cofactors.
Calcitriol
French Fries.
Cofactor necessary for enzyme activity