Yes. Living creatures are subject to these events we call mutations and adaptations, and so almost every biological molecule comes in thousands of variations, e

Yes. Living creatures are subject to these events we call mutations and adaptations, and so almost every biological molecule comes in thousands of variations, each produced reliably by whichever species uses that one. What the molecule actually does is usually determined by a tag hanging off one end. B12 is one of a broad family of cobalamins, which you may read about on Wikipedia. Interestingly, the "cage" containing the cobalt ion is shared with numerous other important molecules, including hemoglobin that carries oxygen in your blood (iron) and chlorophyll plants use to absorb light usefully (magnesium). https://en.m.wikipedia.org/wiki/Vitamin_B12 https://en.m.wikipedia.org/wiki/Vitamin_B12 https://en.m.wikipedia.org/wiki/Porphyrin https://en.m.wikipedia.org/wiki/Porphyrin https://en.m.wikipedia.org/wiki/Chlorophyll https://en.m.wikipedia.org/wiki/Chlorophyll Often we are equipped to modify molecules we eat into the form our bodies like. This routinely happens with drugs, which may have one form that survives the trip through your stomach acids, and another active form it is altered to, often in your liver. This often amounts to stripping off one tag and sticking on another. Amazingly, the porphyrin cage can form spontaneously without any cells involved.