this sounds a lot like indexing that the block explorers do. so you may want to check out the source code of some of the open source block explorers to see how they are doing that like insight https://github.com/bitpay/insight maybe this can clarify your question so others can help you more.

and you keep giving this example:
but 72e... is not a public key! you seem to be doing something wrong so far to this point in your code too.