12SI-labeling

Davies, G. E., and Palek, J. (1981) 12SI-labeling of platelet proteins with Bolton-Hunter reagent. Anal. Biochem. 115, 383—387. 

Injections of 131I given to detect pulmonary embolism can result in false-negative results in the 12SI-labeled fibrinogen test for venous thrombosis. 

Both [5-12SI]iodonaphthylazide (Karlish et al. 1977) and [3H]adaman-tane diazirine (Farley et al. 1980) labeled the a-subunit strongly and the (3-subunit hardly at all. The simplest interpretation of this result is that the (3-subunit is a peripheral protein, tightly attached to the a-subunit. The possibility remains, however, that the (3-subunit is relatively unreactive towards hydrophobic reagents even though the two used in these studies have quite different properties. A further possibility that must be taken into account when considering multisubunit membrane proteins is that (3 penetrates the bi layer but is shielded from the hydrocarbon phase by neighboring a-subunits. ... 

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