Cyanocobalamin is the most common and widely produced form of the chemical compounds that have vitamin B12 activity.
For example, the hadron constituents of atomic nuclei, neutrons and protons, have charges of 0 e and +1 e respectively; the neutron is composed of two down quarks and one up quark, and the proton of two up quarks and one down quark.
When we say that a proton is made up of two up quarks and a down, we mean that its net appearance or net set of quantum numbers match that picture.hen we say that a proton is made up of two up quarks and a down, we mean that its net appearance or net set of quantum numbers match that picture.