Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “PEROXIDASES”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 325 records · Page 18Linked to original sources
PubMed1982

Thyroid hormone formation catalyzed by human thyroid peroxidase: a new and physiological measurement of thyroid peroxidase.

This report describes a method for measurement of TPO activity by the amount of thyroid hormone production. Thyroid hormone formation was accomplished by incubating purified iodine-poor Tg with human TPO for 60 min at 37 C in the presence of free DIT, KI, and an H2O2 source. Newly formed T3 and T4 were measured by radioimmunoassay of the Tg hydrolysates. With this method, TPO-catalyzed iodination of Tg and thyroid hormone formation were measured simultaneously from eight normal thyroid glands and 15 thyroid glands from MMI-treated patients with Graves' disease. Graves' disease TPO showed iodinating activity and T4 formation which was higher than that of TPO from normal thyroids, and there was a positive linear correlation between the iodinating activity and the amount of T4 formation. T3 production by highly active TPO, however, dissociates from the amount of T4 formation and the degree of Tg iodination. Thus, if the activity of TPO is to be measured by the amount of thyroid hormone production, T4 should be used rather than T3. The method of thyroid hormone formation described here provides a new and physiological measurement of TPO activity and should be useful for investigation of the role of human TPO in thyroid hormone formation.

Diiodotyrosine↗
PubMed1980

Detection of platelet associated IgG in immune thrombocytopenia: a new assay employing protein A and peroxidase anti-peroxidase (PROA-PAP).

Immune thrombocytopenia is frequently encountered in medical practice and is generally accepted as being caused by an IgG antibody. The capability of detecting platelet-bound IgG as a diagnostic and therapeutic modality is critical for appropriate care and management of patients with idiopathic thrombocytopenic purpura (ITP), as well as other immune thrombocytopenias. We have modified our previous assay (Br J Haematol 37:265, 1977) by employing protein A and PAP as a labeled antibody. Surface bound platelet IgG was quantitated by phase contrast microscopy after incubation with PAP, graded per 100 platelets and expressed as a reactive index (RI). Controls (n=13) had RIs ranging from 0.49 to 0.72 (mean 0.63 +/- 0.02 SE). The nonimmune thrombocytopenic group (n=7) had an RI ranging from 0.58 to 0.72 (mean 0.64 +/- 0.01 SE). In contrast, the immune thrombocytopenic group (n=28) had RIs ranging from 1.04 to 1.75 (mean 1.43 +/- ;0.03 SE). Platelet-associated IgG was evaluated further by absorbing representative sera samples from each group against washed granulocytes, red cells and platelets. Only when sera from the immune thrombocytopenic group were absorbed against platelets did the reactive indices of pre- and postabsorption samples change significantly. These findings suggest that our assay is clinically applicable in detecting platelet-associated IgG in immune thrombocytopenia and has the advantage of being rapid, reproducible and easy to perform in a clinical laboratory.

Adolescent↗
PubMed1993

Nitrogen regulation of lignin peroxidase and manganese-dependent peroxidase production is independent of carbon and manganese regulation in Phanerochaete chrysosporium.

In this study, a N-deregulated mutant (der8-5) of Phanerochaete chrysosporium was used as a tool to investigate the interrelationships between N, C, and Mn(II) regulation of LIP and MNP production in this organism. The results showed that LIP and MNP production by der8-5 was blocked in excess C medium but not in excess N medium. Furthermore, LIP and MNP production in this organism was subject to Mn(II) regulation regardless of the fact whether it is grown in low N medium or in high N medium. These and other results indicate that N regulation of LIP and MNP production in P. chrysosporium is independent of C and Mn(II) regulation.

Ammonia↗