Interesting question. This is something I'd have to research, but off the cuff (and unofficially) - ultimately it's the AA's that are most important. We know that protein is just amino acid chains (aside from other organic 'substances' that actually make up physical proteins that we can touch and put in our mouths), and when proteins are digested, these chains are broken down and amino's are released into the blood stream.
Re: these 'other organic substances' - I would venture to guess there is some value/importance beyond just the AA's. This is what I'd need to research to give a truly informed answer.
There's no reason you would have a problem. Sufficient protein = sufficient amino acids. The question was whether protein (i.e. chicken, beef) in and of itself was essential vs. just the AA's that proteins are ultimately broken down to.
OP - until there is some kind of conclusive evidence, I'd personally stick with eating food. We evolved to eat and digest food, not dump straight AA's into our system. Supplementing here and there isn't an issue - but I don't think i'd be ready to switch to an AA diet. If for no other reason, satiation sake.