Radiation inactivation method target size

The experimental evidence presented suggests that the RIS and target size correspond to the size of the polypeptide portion of the molecule and not to associated structures such as lipids or carbohydrates, even though, as in the case of carbohydrates, these compounds are covalently bound to the protein. Therefore it is incorrect to state that the RIS obtained by the radiation inactivation method gives the of lipid-associated proteins, detergent-associated proteins or glycoproteins. 

An application of radiation induced-inactivation, is the determination of the size of the enzyme (216, 217). Nevertheless, care should be taken when using this method as secondary damage due to free radicals generated in the local environment of an enzyme, can influence the apparent target size determined (218). Also, it might be that radiation damage is a surface phenomenon thus not dependent on the volume of the protein but on its surface (19). 

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