5-Iodosalicylate

Iodosalicylic acid (2-hydroxy-5-iodobenzoic acid) [119-30-2] M 264.0, m 197 pKj 2.65, pK 13.05. Crystd from water. 

The adenosine moiety binds in a hydrophobic crevice, lined by residues from )8A, aB, 8B, and 8D, at the carboxyl end of the parallel jS-pleated sheet. Similar hydrophobic pockets are found in all the dehydrogenases, and equivalent residues are listed in Table VIII. The specificity of the hydrophobic pocket is for aromatic groups rather than for adenine in particular as is shown by the binding of 5-iodosalicylate to LADH (. 7) and the affinity of an iodofluorescein dye to LDH ( 8). The pocket in GAPDH is somewhat less hydrophobic in its interior because of the presence of Asp-6 and Asn-31. The adenine ring is situated between Phe-34 and Phe-99. 

Stadeler s discovery of the formation of chloranil from tyrosine led to the supposition that tyrosine was a derivative of salicylic acid, and on this assumption Schmidt and Nasse attempted to synthesise tyrosine from ethylamine and iodosalicylic acid, and from amidosalicylic and ethyl iodide, but did not succeed. On heating tyrosine they obtained a base CgHuNO, which they thought analogous to the one Schmidt had obtained by heating amidosalicylic acid on this account they held to the accuracy of the theory that tyrosine was ethylamidosalicylic acid. 

A glycoprotein (mol. wt, 1.5 X 10 ) has been isolated from whole human platelets by affinity chromatography on immobilized wheat-germ agglutinin. Extraction of the whole platelets with lithium di-iodosalicylate released three major glycoprotein fractions. 

See under 4-Iodosalicylic Acid. 1-Iodonaphthalene [oi-Iodonaphthalene, a-naphthyl iodtde)... 

Spacer. After iodination to the 4-Azido-3- iodosalicylic acid derivative it was found suitable for the radioactive labelling of avermectin binding proteins. The... 

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