A modified version of the enzyme human superoxide dismutase (hSOD) in which polyethylene glycol (a polymer made up of ethylene glycol monomers) is combined with the hSOD molecule. The PEG seems to wrap around or about the enzyme in such a way that the whole complex is able to exist in the blood for longer periods of time than the unmodified hSOD enzyme. This is because the PEG effectively camouflages the hSOD molecule and hence protects it from being inactivated by the body’s own defense mechanisms in the bloodstream. This technology is important in that hSOD is used to fight certain diseases by injecting it into the body. However, the SOD must be present in the body for extended periods of time in order to effectively work, and since the injected SOD is a foreign molecule, the body tries to destroy it (and hence its function) as quickly as possible.