thyroid hormone generation Reactome:R-HSA-209968 Note that this term does not fall under the general GO definition for biosynthetic processes, which is 'The chemical reactions and pathways resulting in the formation of... ', because thyroid hormones can only be formed by the proteolysis of a larger molecule (see term definition). The word 'generation' is therefore used in place of biosynthesis. GO:0006590 The formation of either of the compounds secreted by the thyroid gland, mainly thyroxine and triiodothyronine. This is achieved by the iodination and joining of tyrosine molecules to form the precursor thyroglobin, proteolysis of this precursor gives rise to the thyroid hormones. thyroid hormone metabolic process