Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.11.1.7 (peroxidase)
 65,474 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

18 subjects, 9 males and 9 females, were examined regarding salivary oxidation-reduction potential, salivary flow rate, salivary peroxidase activity, oxidation-reduction potential of dental plaque samples, and dental health. Both the peroxidase activity, expressed as the salivary lactoperoxidase, and the salivary oxidation-reduction potential increased with increasing salivary flow rate. The variation of these variables was obviously due to changes in salivary flow rate during the day. The remarkably slight differences in peroxidase activities, oxidation-reduction potentials and salivary flow rate in this study did not have any marked correlation with the clinical recordings of the test groups.
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PMID:The correlation between salivary peroxidase activity, salivary flow rate, and the oxidation-reduction potentials of human saliva and dental plaque suspensions. 0 73

Aldehyde-resistant, diaminobenzidine-stained endogenous peroxidases form ideal markers for the biochemical endpoints of hormone stimulation and differentiation of certain mammalian cells and tissues. The lactoperoxidase (LPO)-type of endogenous peroxidases are synthesized by the acinar cells of the salivary, Harderian, lacrimal and mammary glands and are present in their secretions. These LPO-type enzymes, that are inhibited by cyanide and aminotriazole, appear to operate extracellularly as bactericidal agents in milk and in other biological fluids. In the mammary gland, lactoperoxidase is a consistent marker enzyme for differentiated acinar cells engaged in lactogenesis. Myeloperoxidase (MPO)-type endogenous peroxidases are prominent markers for the GERL endomembrane system and differentiated lysosomes in certain cells of the reticuloendothelial system and phagocytes. MPO is prominent within eosinophils, peritoneal macrophages and in Kupffer cells. The MPO-type endogenous peroxidases function primarily within lysosomes as bactericidal agents. Thyroid peroxidase (TPO) is relegated to the cisternae of the granular endoplasmic reticulum and Golgi apparatus, to apical cytoplasmic vesicles and to the luminar cell membrane surface of acinar cells. The enzyme is probably activated at release and functions both in the organification reaction (T leads to To) and in the biosynthesis of thyroxine. Thyroid stimulating hormone (TSH) appears to play a key role in the regulation of TPO levels and activity in the thyroid gland. Certain tissues displaying growth-dependency on estrogen (i.e., uterus, cervix, vagina and the DMBA-induced rat mammary tumor) synthesize and secrete endogenous peroxidase into their lumina. These enzymes serve as important marker proteins of estrogen action, in that they occur distal to the binding of estrogen to its receptor protein. Estrogen antagonists, particularly CI-628 (Parke-Davis) and Nafoxidine (Upjohn) that appear to function through the estrogen receptor mechanism, also induce synthesis of the reproductive tract endogenous peroxidase but inhibit growth of these tissues. Progesterone antagonizes the synthesis of the reproductive tract peroxidases and inhibits growth of the tissues as well, in part, through the reduction of the cytosol estrogen receptor protein. Endogenous peroxidase activity appears to represent a reliable marker for rodent breast cancer tissues displaying dependency for estrogen and is of potential interest as a diagnostic marker protein in human breast cancer. Rat uterine peroxidase (UP) has been investigated by microelectrophoretic techniques. The molecular weight of UP has been determined in the range of 100,000 by using polyacrylamide gradient gels in the absence and presence of nonionic and anionic detergents. The isoelectric point of UP is located between pH 4.5 and 5.9. Employing the two-dimensional combination of isoelectric focusing and gel gradient electrophoresis, UP was separated into two subunits, one having a molecular weight of 70,000, the other less than 20,000.
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PMID:Mammalian endogenous peroxidases as cellular markers and as biosynthetic endpoints of hormone-mediated activity: viewpoint from cytochemistry. 22 20

Purified milk lactoperoxidase and endogenous human salivary peroxidase were used to label the proteins of whole mouth saliva with [125I]iodide. The proteins were then analyzed by isoelectric focusing or they were subjected to one-dimensional polyacrylamide gel electrophoresis at pH 8.4. The radioactivity of the resolved protein fractions was determined. There were three to four major and four to five minor areas of radioactivity which were carried together with more or less distinctive protein fractions. Amylase and albumin were shown to be the most effective in binding [125I]iodide. No significant differences were observed in the iodination patterns of salivary proteins iodinated in the presence of endogenous saliva peroxidase and those iodinated in the presence of added milk lactoperoxidase. Hydrogen peroxide was necessary for iodination to take place. The significance of iodoproteins and the role of salivary peroxidases in the nonthyroidal metabolism of iodine are discussed.
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PMID:Enzymatic iodination of salivary proteins by the 125I-lactoperoxidase system. 26 76

The purpose of this review is to summarize recent progress in the field of genetic protein polymorphisms found in human saliva since 1972. Prior to 1972 most of the investigations were related to amylase. The genetics of salivary amylase will not be considered here, since it has recently been thoroughly reviewed elsewhere (Merritt and Karn, 1977). In this review, special attention will be devoted to the complex interrelationships of the proline-rich (Pr), double-band (Db), acidic protein (Pa), and peroxidase (SAPX) systems. The biochemically related Pr, Db, and Pa systems show distinctive genetic patterns, and there are associations between the phenotypes indicating linkage relationships. There is also evidence for probable interaction of products of the Pa and SAPX loci. Electrophoretic properties of these proteins can be defined in several gel systems, permitting an accurate definition of phenotypes. The usefulness and limitations of the different gel systems in the interpretation of these electrophoretic patterns will be illustrated. Allelic frequencies of the systems to be discussed are given in Table I. To aid comprehension, the systems will be discussed in logical rather than historical sequence.
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PMID:Genetic protein polymorphisms in human saliva: an interpretive review. 34 95

The lactoperoxidase (LPO) activity in guinea-pig milk and saliva has been investigated in sows suckling normal young, and young orally infected with Escherichia coli. There was a 5-fold increase in activity in milk during the 3--4 weeks of lactation; infection of the young did not alter this. There was no comparable increase in lactoperoxidase activity of saliva during this same period, either in the infected or non-infected group. The antibacterial activity of milk from sows suckling normal young increased with the lactoperoxidase, and this bactericidal activity could be reversed by LPO inhibitors such as penicillamine and cysteine but not by addition of sufficient iron to saturate the lactoferrin. In milk from sows suckling infected young, bacteriostatic activity occurring in samples from about 14 days after infection needed iron or both iron and penicillamine (or cysteine) for reversal, indicating that both the antibody-lactoferrin system and the LPO system may be involved in the infected state.
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PMID:Lactoperoxidase activity in guinea-pig milk and saliva: correlation in milk of lactoperoxidase with bactericidal activity against Escherichia coli. 38 28

Tropolone (TR) and 3-hydroxy-4-pyrone were investigated for antithyroid activity following the finding that the 2-hydroxy-oxo pyridine, 3-hydroxy-4(1H)-pyridone (DHP, I), is goitrogenic. Both compounds inhibited the thyroidal uptake of radioiodine in rats and resembled the thioamide drugs in inhibiting the organic binding of iodine by the thyroid gland rather than the trapping of iodide, but were weaker binding inhibitors than 6-methyl-2-thiouracil (MeTU). Both compounds also inhibited the iodination of bovine serum albumin and thyroglobulin, catalyzed by thyroidperoxidase (TPO), lactoperoxidase (LPO), chloroperoxidase (CPO) and horseradish peroxidase (HPO) in vitro. The inhibitory effect of TR but not that of 3-hydroxy-4-pyrone was antagonized by ferrous ions. When fed to mice at levels of intake expected to produce goitre both compounds were toxic and caused severe liver damage. Thyroid enlargement was not observed in any of these feeiding experiments, but the thyroids of mice fed 0.1% TR showed moderate hyperplasia. It was concluded that both compounds are weakly goitrogenic. Hyperactivity was observed in the mice fed TR which may be associated with inhibition of catechol methyl transferase (COMT).
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PMID:Antithyroid and antiperoxidase activity of tropolone and 3-hydroxy-4-pyrone. 47 52

There is genetic polymorphism of the peroxidase of human saliva, but not of leukocytes. The phenotypes are determined by autosomal inheritance, the phenotype of fast mobility (SAPX 1) being determined by homozygosity for a recessive gene (SAPX1) and the phenotypes of slow mobility (SAPX 2 and SAPX 3) being determined by two different genes, SAPX2 and SAPX3, with completely dominant expression at the same locus. The phenotypes are modified by varying degrees of endogenous proteolysis. The SAPX 2 and SAPX 3 types appear to be genetically controlled modifications of SAPX 1 rather than different primary gene products, because of their completely dominant inheritance, their larger molecular size compared to SAPX 1, and their dissociation with 2-mercaptoethanol to give SAPX 1. The acidic protein type Pa 1 is always found in association with SAPX 2, and an uncommon variant type Pa 2 is associated with SAPX 3. The most likely hypothesis is that the genes Pa1 and Pa2 produce products which modify the SAPX 1 type. When the Pa type is Pa 0, the SAPX phenotype is SAPX 1. Since 2-mercaptoethanol can dissociate the Pa 1 protein into a probable monomeric form, and can dissociate SAPX 2 and SAPX 3 to give SAPX 1, it is probable that Pa 1 and Pa 2 monomers complex with SAPX 1 through disulfide bonds to give SAPX 2 or SAPX 3 types. The frequencies of the genes determining the SAPX types are the same as those for Pa: SAPX1 and Pa0 = 0.787, SAPX2 and Pa1 = 0.208, SAPX3 and Pa2 = 0.005.
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PMID:Salivary peroxidase (SAPX): genetic modification and relationship to the proline-rich (Pr) and acidic (Pa) proteins. 84 56

Myeloperoxidase (MPO), which displays considerable amino acid sequence homology with thyroid peroxidase (TPO) and lactoperoxidase (LPO), was tested for its ability to catalyze iodination of thyroglobulin and coupling of two diiodotyrosyl residues within thyroglobulin to form thyroxine. After 1 min of incubation in a system containing goiter thyroglobulin, I-, and H2O2, the pH optimum of MPO-catalyzed iodination was markedly acidic (approximately 4.0), compared to LPO (approximately 5.4) and TPO (approximately 6.6). The presence of 0.1 N Cl- or Br- shifted the pH optimum for MPO to about 5.4 but had little or no effect on TPO- or LPO-catalyzed iodination. At pH 5.4, 0.1 N Cl- and 0.1 N Br- had a marked stimulatory effect on MPO-catalyzed iodination. At pH 4.0, however, iodinating activity of MPO was almost completely inhibited by 0.1 N Cl- or Br-. Inhibition of chlorinating activity of MPO by Cl- at pH 4.0 has been previously described. When iodination of goiter thyroglobulin was performed with MPO plus the H2O2 generating system, glucose-glucose oxidase, at pH 7.0, the iodinating activity was markedly increased by 0.1 N Cl-. Under these conditions iodination and thyroxine formation were comparable to values observed with TPO. MPO and TPO were also compared for coupling activity in a system that measures coupling of diiodotyrosyl residues in thyroglobulin in the absence of iodination. MPO displayed very significant coupling activity, and, like TPO, this activity was stimulated by a low concentration of free diiodotyrosine (1 microM). The thioureylene drugs, propylthiouracil and methimazole, inhibited MPO-catalyzed iodination both reversibly and irreversibly, in a manner similar to that previously described for TPO-catalyzed iodination.
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PMID:Myeloperoxidase-catalyzed iodination and coupling. 131 92

Whole saliva from 53 children who had been tonsillectomized when they were younger than 4 years old was analyzed for selected antimicrobial proteins and oral mutans streptococci 3-4 years after the operation. The results were compared with those from age- and gender-matched control children with no history of tonsillectomy. The salivary analyses comprised both immune (total IgA, IgG and IgM) and selected nonimmune (lactoferrin, myeloperoxidase, salivary peroxidase) antimicrobial proteins. Specific IgA and IgG antibodies against viral antigens (adeno-, cytomegalo-, respiratory syncytial- and Epstein-Barr-viruses) and against Streptococcus mutans cells were quantitated in both groups. The tonsillectomized children had statistically significantly higher concentrations of all immunoglobulin isotypes (P 0.001) as well as of lactoferrin (P less than 0.005), and myeloperoxidase (P less than 0.001) in saliva. However, no differences were found in the numbers of cariogenic mutans streptococci or in the total oral aerobic flora. In line with the streptococcal counts, no differences existed in anti-S. mutans IgA or IgG titers between the groups. Most antibodies against viruses, especially of IgG isotype, were significantly (P less than 0.001) higher in saliva of tonsillectomized children than in that of the controls. The results suggest that, within a long run, the humoral immune status of human saliva is not weakened by tonsillectomy. Also, mainly serum-derived antimicrobial proteins (myeloperoxidase, lactoferrin, IgG) exist in high concentrations in whole saliva after tonsillectomy.
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PMID:Salivary antimicrobial proteins and mutans streptococci in tonsillectomized children. 132 24

Fluoride (F-) inhibition of peroxidase activity in whole saliva and of recombinant human myeloperoxidase was investigated using thiocyanate (SCN-) and chloride (Cl-) as substrates. At pH 5.5, SCN(-)-linked activity in whole saliva reduced to < 40% of its initial value at F- concentration of 20 mM, while Cl- linked activity was maintained at 90% of its initial value for the same F-concentration. Based on this Cl(-)-linked activity, the contribution of natural MP to the SCN(-)-linked activity in whole saliva can be calculated. This shows a total inhibition of SCN- dependent activity of salivary peroxidase (SP) for F-concentrations > 10 mM. At a 20 mM F-concentration, recombinant MP activity reduced to 66% of its initial value with SCN-, against 88% for Cl- as substrate. This inhibition of the SCN- linked SP activity is enhanced at acid pH for a F-concentration of 20 mM: 26% residual activity at pH 5 for whole saliva + SCN-against 93% for whole saliva + Cl-; 61% for recombinant MP + SCN- and 88% for MP + Cl-. Calculated activities for SP alone showed a total inhibition at pH 5, while the inhibition was absent at pH 6.5. F-inhibition in whole saliva could also be suppressed by the addition of hydrogen peroxide.
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PMID:Fluoride inhibition of SCN- and Cl-peroxidase activities in whole saliva and of recombinant myeloperoxidase. Influence of pH and hydrogen peroxide concentration. 133 90


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