Tyrosine astatination

In mitochondrial research the phosphate-transporting protein from rat liver mitochondria has been labeled with ° Hg-mersalyl At For protein labeling with astatine (alpha emitter) the following procedures may be u reaction of the protein with p-astatobenzoic acid < ndensation reaction with peptide bond and protein acetylation While labeling by the above procedures seems to be sufficiently stable a remarkable instability of the At-label was obserwd when astatinated protein was prepared electrophoretically 202) jjjg results of these authors indicate that the tyrosine-astatine bond is unstable. The conclusion of Vau an et al. that astatinated proteins lore as much as 50% of their biological activity and, in addition, are extremely toxic, is very serious. 

The electrophilic character of astatine in aqueous acidic solution has been taken advantage of to prepare carrier-free astatotyrosine (10), an important compound for biomedical investigations53. An optimal yield of ca 90% was obtained if an aqueous solution of astatine together with tyrosine was dissolved in a mixture of perchloric and acetic acid and heated in sealed ampoules to 150-160 °C for about 30 minutes. Raising the temperature to... 

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