Thyroid peroxidase

from Wikipedia, the free encyclopedia
Thyroid peroxidase
Properties of human protein
Mass / length primary structure 919 amino acids
Secondary to quaternary structure Heterodimer
Cofactor Ca 2+ , heme  b
Isoforms TPO1, TPO2, TPO3, TPO4, TPO5, TPO6, 2-3, 2-4
Identifier
Gene name TPO
External IDs
Enzyme classification
EC, category 1.11.1.8 ,  oxidoreductase
Response type Redox reaction
Substrate Iodide , H 2 O 2
Products Iodine , H 2 O
Occurrence
Homology family Hemperoxidases
Parent taxon Chordates

Thyroid peroxidase (TPO) (also: iodide peroxidase , systematic name: iodide hydrogen-peroxide oxidoreductase) is the enzyme that the first reaction step in the synthesis of the thyroid hormones from the amino acid tyrosine catalysed . The enzyme is produced in all chordates . Defects in the enzyme due to mutations in the TPO - gene can in humans to specific forms of hypothyroidism lead.

Thyroid peroxidase is a transmembrane protein that occurs in the apical cell membrane of thyroid cells . Autoantibodies against thyroid peroxidase (thyroid peroxidase antibodies , TPO-AK) can be detected in various autoimmune diseases of the thyroid gland ( autoimmune thyroid disorders ) .

Catalyzed reactions

L-tyrosine+ I - + H + + H 2 O 2 ⇒ 3-iodo-L-tyrosine+ 2 H 2 O

Iodide is oxidized to iodine, which is immediately substituted on tyrosine.

3-iodo-L-tyrosine+ I - + H + + H 2 O 2 ⇒ 3,5-diiodo-L-tyrosine+ 2 H 2 O

Iodide is oxidized to iodine, which is immediately substituted for 3-iodotyrosine.

further reading

  • Lothar-Andreas Hotze, Petra-Maria Schumm-Draeger. Thyroid diseases. Diagnosis and therapy. Berlin 2003, ISBN 3-88040-002-4 .
  • T. Hosoya, Y. Kondo, N. Ui: Peroxidase activity in thyroid gland and partial purification of the enzyme . In: Journal of Biochemistry . tape 52 , September 1962, ISSN  0021-924X , p. 180-189 , PMID 13964156 .
  • Noeleen B. Loughran, Brendan O'Connor, Ciarán Ó'Fágáin, Mary J. O'Connell: The phylogeny of the mammalian heme peroxidases and the evolution of their diverse functions . In: BMC Evolutionary Biology . tape 8 , 2008, ISSN  1471-2148 , p. 101 , doi : 10.1186 / 1471-2148-8-101 , PMID 18371223 , PMC 2315650 (free full text).
  • Y. Song, N. Driessens, M. Costa, X. De Deken, V. Detours, B. Corvilain, C. Maenhaut, F. Miot, J. Van Sande, M.-C. Many, JE Dumont: Roles of hydrogen peroxide in thyroid physiology and disease . In: The Journal of Clinical Endocrinology and Metabolism . tape 92 , no. October 10 , 2007, ISSN  0021-972X , p. 3764-3773 , doi : 10.1210 / jc.2007-0660 , PMID 17666482 .

Web links

Wikibooks: Biochemistry and Pathobiochemistry: Tyrosine Metabolism  - Learning and Teaching Materials

Individual evidence

  1. ↑ enzyme - 1.11.1.8 in the KEGG
  2. ↑ UniProt P07202
  3. ↑ Sandra M. McLachlan, Yuji Nagayama, Pavel N. Pichurin, Yumiko Mizutori, Chun-Rong Chen, Alexander Misharin, Holly A. Aliesky, Basil Rapoport: The link between Graves' disease and Hashimoto's thyroiditis: a role for regulatory T cells . In: Endocrinology . tape 148 , no. December 12 , 2007, ISSN  0013-7227 , p. 5724-5733 , doi : 10.1210 / en.2007-1024 , PMID 17823263 .
  4. ↑ S. Mariotti, P. Caturegli, P. Piccolo, G. Barbesino, A. Pinchera: antithyroid peroxidase autoantibodies in thyroid diseases . In: The Journal of Clinical Endocrinology and Metabolism . tape 71 , no. 3 , September 1990, ISSN  0021-972X , p. 661-669 , doi : 10.1210 / jcem-71-3-661 , PMID 2168432 .
  5. ↑ KEGG pathway: Autoimmune thyroid disease