Biochemistry of Amino Acids - A. Majster 1961

Natural Amino Acids
Other Natural Amino Acids
Halogen-Containing Amino Acids

Among halogen-containing Amino Acids, 3,5-diiodo-L-Tyrosine [257] was one of the first to be discovered, identified in certain marine organisms and as a component of thyroid Proteins.

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3,5-Dibromotyrosine also occurs naturally, having been found in certain coral species [258] and, along with monobromotyrosine, in starfish Tissues [259].

L-Thyroxine is a constituent of thyroid protein; its isolation has been described and its Structure established [260, 261]:

Relatively recently, two additional iodine-containing amino acids were discovered in thyroid tissue. Monoiodotyrosine was identified through chromatographic analysis of thyroid hydrolysates [262—264]; it does not appear to be a breakdown product of diiodotyrosine. Monoiodotyrosine is also found in marine Sponges [259].

3, 3', 5-Triiodo-L-thyronine was isolated from the bovine Thyroid Gland [265]; furthermore, it can be detected in tryptic hydrolysates of rat thyroid glands following the administration of І131-iodide.

Like thyroxine, triiodothyronine is also present in the body in a free state. Interestingly, in the goiter-Prevention assay, triiodothyronine exhibits approximately 5 times greater biological activity than thyroxine. Recent studies indicate the presence of diiodothyronine and monoiodohistidine in the thyroglobulin of dogs and rats following the administration of sodium І131-iodide [266].



Last update: 06/08/2026

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