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.
Figure 1 would suggest that the up and down quarks are simply 1/3 of the mass of the proton and of the neutron: about 0.313 GeV/c2, or maybe a bit more or less due to the energy needed to hold the quarks together in the proton.