Distribution and forms of iodine in human oral cavity

Neither iodinated proteins nor iodinated, low-molecular weight compounds (e.g. iodinated tyrosine derivatives) could be detected in concentrated human salivary supernatant by using the Ce(SO4)2-method either directly or after thin-layer chromatography. Salivary sediment contained free I- ions, loosely bound iodine (released with saline) and strongly bound iodine (released with sonication, detergent and acid hydrolysis). A positive correlation between salivary and crevicular excretion of I- from plasma was observed. Thiocyanate ions, which competitively inhibit peroxidase-catalysed oxidation and iodination reactions and which are abundant in human saliva, possibly prevent the coupling of I- to protein in vivo although some human salivary proteins are very susceptible to iodination in vitro.