Cofactor vs Coenzyme
Many enzymes have to link to their respective helpers to promote optimal arrangement of their atoms and proper functioning. Cofactors and coenzymes are two sorts of such helper molecules.
Cofactors are inorganic ions. Examples include magnesium (Mg++), selenium (Se++) and iron (Fe++).
The human being is one of the few members of the animal kingdom that can not synthesize vitamin C.
In 1959 J.J. Burns showed that the few mammals susceptible to scurvy are unable to produce the active enzyme, L-gulonolactone oxidase, involved in the conversion of blood glucose to ascorbic acid, in their livers. The synthesis of vitamin C is involving four enzymes. Man has the first three enzymes. The missing fourth enzyme completely blocks the liver production of ascorbic acid.
Other animals, are not able to synthesize ascorbic acid, are primates, some birds, guinea pigs, and fruit bats.
Vitamin B1 is also known as thiamine belongs to water-soluble vitamins of B complex. In the human body about 80% of thiamin are presented in the form of thiamin diphosphate (TDP). Another common name for thiamin diphosphate is thiamin pyrophosphate (TPP).
Vitamin B2, also known as riboflavin, refers to water-soluble B vitamins. Depending on the source, from which it was derived, it was called differently: lactochrome (from milk), hepatoflavin (from liver), ovoflavin (from eggs), verdoflavin (from plants).