Scientists Make Artificial Protein Mimic Blood

Al writes "Researchers at the University of Pennsylvania have created a protein that can carry and deliver oxygen — a useful step towards developing artificial blood. This would avoid the problems involved with donor blood — contamination, limited storage, and short supply — and lead to easier and faster blood transfusions on the battlefield and in trauma cases. The Penn researchers used three amino acids to make a four-helix columned protein structure put a smaller structure, called a heme, inside it. The heme is a large flat molecule that has an iron atom at its center, which oxygen binds to. The researchers also made the protein structure flexible, so that it can open to receive the oxygen and close again without letting any water in. They did this by linking together the helical columns with loops to restrict their motions, giving the final structure a candelabra shape."

Comments

Interesting and cool... however

[tpjunkie]

They fail to give any meaningful data on its oxygen dissociation curve against pH, so we have no idea how it will perform as an oxygen transporter at physiological conditions. Also missing is any information on whether histidine groups are present above and below the heme which are quite important for regulating the binding and release of O2. While I am suitably impressed with their engineering of a protein from scratch, I will hold off on kudos for creating something useful until I see some hard data.

Re:Various Questions

[pete-classic]

More to the point, does it induce cardiac infarction, like PolyHeme? (And is the FDA going to foist it on the unconscious without consent, as they did PolyHeme?)

-Peter

Re:Artificial hemoglobin?

[ColdWetDog]

Hemoglobin carries oxygen just fine. Why can't they use it?

Remember, hemoglobin is just one part of the red blood cell - that's the 'thing' that delivers blood to tissues. If you just dump straight hemoglobin in the system, it gets chewed up quickly (like most random proteins) and clobbers the kidneys. (see the interesting wikipedia article for some background. Researchers have tried various 'synthetic' hemoglobins to do just that and so far, they haven't worked well.

Interestingly, there is a bovine hemoglobin / albumin conjugate that is approved for dogs. So it's possible that some combination of an oxygen carrying protein sans full red blood cell will work, but we haven't got there yet.