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La thyroglobuline, protéine iodée naturelle
Author(s) -
Nunez J.
Publication year - 1967
Publication title -
journal of labelled compounds
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.432
H-Index - 47
eISSN - 1099-1344
pISSN - 0022-2135
DOI - 10.1002/jlcr.2590030202
Subject(s) - halogenation , halogen , chemistry , iodine , thyroglobulin , molecule , bromine , stereochemistry , organic chemistry , thyroid , biology , endocrinology , alkyl
Certain critical observations can be made with regard to the preparation and properties of artificially halogenated proteins on the basis of the study of the iodination and biosynthesis of thyroglobulin in the thyroid gland and its physico‐chemical properties. It appears that iodination causes two types of changes. The first has to do with halogenation method used. The damage is caused by the actual iodination conditions and can be avoided if the chemical iodination methods are replaced by enzymatic techniques. The second is an inevitable consequence of the introduction of the halogen (which is tantamount to changing the primary structure of the molecule). The physico‐chemical properties (probably the conformation of the protein) depend on the halogen content and its distribution. In the case of thyroglobulin, two types of change are observed. For fairly low halogen contents, each iodine atom introduced causes an increase in the sedimentation factor (from 17 to 20 S). When the iodine content is increased, the molecule, which has hitherto been broken down by the detergent into sub‐units of 12 S, develops a resistance to this treatment, so that iodination modifies the interaction between sub‐units.