Biology:Lactoperoxidase

From HandWiki
Short description: Mammalian protein found in Homo sapiens


A representation of the 3D structure of the protein myoglobin showing turquoise α-helices.
Generic protein structure example


Lactoperoxidase is a peroxidase enzyme secreted from mammary, salivary and other mucosal glands including the lungs, bronchii and nose[1] that functions as a natural and the first line of defense against bacteria and viruses.[2] Lactoperoxidase is a member of the heme peroxidase family of enzymes. In humans, lactoperoxidase is encoded by the LPO gene.[3][4]

Lactoperoxidase catalyzes the oxidation of several inorganic and organic substrates by hydrogen peroxide.[5] These substrates include bromide and iodide and therefore lactoperoxidase can be categorised as a haloperoxidase. An other important substrate is thiocyanate. The oxidized products produced through the action of this enzyme have potent and non-specific bactericidal and antiviral activities, including destruction of the influenza virus. Lactoperoxidase together with its inorganic ion substrates, hydrogen peroxide, and oxidized products is known as the lactoperoxidase system.[6] Hence LPO is considered a very important defense against invasive bacteria and viral agents such as influenza and the SARS-CoV-2 virus when sufficient iodine is provided.[7][8][9]

The lactoperoxidase system plays an important role in the innate immune system by killing bacteria in milk and mucosal (linings of mostly endodermal origin, covered in epithelium, which are involved in absorption and secretion) secretions hence augmentation of the lactoperoxidase system may have therapeutic applications. Furthermore, addition or augmentation of the lactoperoxidase system has potential applications in controlling bacteria in food and consumer health care products. The lactoperoxidase system does not attack DNA and is not mutagenic.[10] However, under certain conditions, the lactoperoxidase system may contribute to oxidative stress.[11] Furthermore, lactoperoxidase may contribute to the initiation of breast cancer, through its ability to oxidize estrogenic hormones producing free radical intermediates.[12]

Structure

The structure of lactoperoxidase consists mainly of alpha-helices plus two short antiparallel beta-strands.[13] Lactoperoxidase belongs to the heme peroxidase family of mammalian enzymes that also includes myeloperoxidase (MPO), eosinophil peroxidase (EPO), thyroid peroxidase (TPO), and prostaglandin H synthase (PGHS). A heme cofactor is bound near the center of the protein.[14]

Function

Lactoperoxidase catalyzes the hydrogen peroxide (H2O2) oxidation of several acceptor molecules:[15]

  • reduced acceptor + H2O2 → oxidized acceptor + H2O

Specific examples include:

Source of the hydrogen peroxide (H2O2) usually is the reaction of glucose with oxygen in the presence of the enzyme glucose oxidase (EC 1.1.3.4) that also takes place in saliva. Glucose, in turn, can be formed from starch in the presence of the saliva enzyme amyloglucosidase (EC 3.2.1.3).

These relatively short lived oxidized intermediates have potent bactericidal effects, hence lactoperoxidase is part of the antimicrobial defense system in tissues that express lactoperoxidase.[6] The lactoperoxidase system is effective in killing a range of aerobic[18] and certain anaerobic microorganisms.[19] Research (1984): "The effect of lactoperoxidase-thiocyanate-hydrogen peroxide mixtures on bacteria is dependent on experimental conditions. If the bacteria are cultured after the exposure to lactoperoxidase-thiocyanate-hydrogen peroxide on nutrient agar under aerobic conditions, they may not grow, whereas they grow readily on blood agar under anaerobic conditions."[20] In its antimicrobial capacity, lactoperoxidase appears to acts synergistically with lactoferrin[21] and lysozyme.[22]

Applications

Lactoperoxidase is an effective antimicrobial and antiviral agent. Consequently, applications of lactoperoxidase are being found in preserving food, cosmetics, and ophthalmic solutions. Furthermore, lactoperoxidase have found application in dental and wound treatment. Finally lactoperoxidase may find application as anti-tumor and anti viral agents.[23] Lactoperoxidase has been used with radioactive iodine to selectively label membrane surfaces.[24]

Dairy products

Lactoperoxidase is an effective antimicrobial agent and is used as an antibacterial agent in reducing bacterial microflora in milk and milk products.[25] Activation of the lactoperoxidase system by addition of hydrogen peroxide and thiocyanate extends the shelf life of refrigerated raw milk.[15][26][27][28] It is fairly heat resistant and is used as an indicator of overpasteurization of milk.[29]

Oral care

A lactoperoxidase system is claimed to appropriate for the treatment of gingivitis and paradentosis.[30] Lactoperoxidase has been used in toothpaste or a mouthrinse to reduce oral bacteria and consequently the acid produced by those bacteria.[31]

Cosmetics

A combination of lactoperoxidase, glucose, glucose oxidase (GOD), iodide and thiocyanate is claimed to be effective in the preservations of cosmetics.[32]

Cancer

Antibody conjugates of glucose oxidase and to lactoperoxidase have been found to effective in killing tumor cells in vitro.[33] In addition, macrophages exposed to lactoperoxidase are stimulated to kill cancer cells.[34] Knockout mice deficient in lactoperoxidase suffer ill-health and develop tumors.[35]

Clinical significance

Innate immune system

The antibacterial and anti-viral activities of lactoperoxidase play an important role in the mammalian immune defense system; the lactoperoxidase system is considered the first line of defense against airborne bacteria and viral agents.[36][37][38] Importantly, lactoperoxidase is also extruded into the lung, bronchii and nasal mucus.[39]

Hypothiocyanite is one of the reactive intermediates produced by the activity of lactoperoxidase on thiocyanate and hydrogen peroxide produced by dual oxidase 2 proteins, also known as Duox2.[40][41] Thiocyanate secretion[42] in cystic fibrosis patients is decreased, resulting in a reduced production of the antimicrobial hypothiocyanite and consequently contributes to increased risk of airway infection.[43][44]

Viral infections

Peroxidase-generated hypoiodous acid (HOI), hypoiodite and hypothiocyanite all destroy the herpes simplex virus[45] and human immunodeficiency virus.[46] Both the hypothiocyanite and the hypoiodate ion products are very potent and importantly non-specific antiviral oxidants which are lethal, even in small concentrations, to the influenza virus.[47] The anti-viral activity of lactoperoxidase is enhanced with increasing concentrations of iodide ion.[48] This enzyme has been shown effective against a highly dangerous and tough RNA virus (poliovirus) and a long-lived DNA virus (vaccina).[49]

Bacterial infections

The duox2-lactoperoxidase system has been shown to offer protection against many dozens of bacteria and mycoplasmas including varieties of the clinically important Staphylococcus and many Streptococcus types.[50] The lactoperoxidase system efficiently inhibits the common helicobacter pylori in buffer; however, in whole human saliva, it seems to have a weaker effect against this microbe.[51] It has been shown that lactoperoxidase in the presence of thiocyanide can catalyze the bactericidal and cytotoxic effects of hydrogen peroxide under specific conditions when hydrogen peroxide is present in excess of thiocyanide.[20] The combination of lactoperoxidase, hydrogen peroxide and thiocyanide is much more effective than hydrogen peroxide alone to inhibit bacterial metabolism and growth.[52]

Breast cancer

The oxidation of estradiol by lactoperoxidase is a possible source of oxidative stress in breast cancer.[11][12] The ability of lactoperoxidase to propagate a chain reaction leading to oxygen consumption and intracellular hydrogen peroxide accumulation could explain the hydroxyl radical-induced DNA base lesions recently reported in female breast cancer tissue.[11] Lactoperoxidase may be involved in breast carcinogenesis, because of its ability to interact with estrogenic hormones and oxidise them through two one-electron reaction steps.[12] Lactoperoxidase reacts with the phenolic A-ring of estrogens to produce reactive free radicals.[53] In addition, lactoperoxidase may activate carcinogenic aromatic and heterocyclic amines and increase binding levels of activated products to DNA, which suggests a potential role of lactoperoxidase-catalyzed activation of carcinogens in the causation of breast cancer.[54]

Oral Care

During the last decades, several clinical studies describing the clinical efficacy of the lactoperoxidase system in a variety of oral care products (tooth pastes, mouth rinses) have been published. After showing indirectly, by means of measuring experimental gingivitis and caries parameters, that mouth rinses[55][56] containing amyloglucosidase (γ-amylase) and glucose oxidase activate the lactoperoxidase system, the protective mechanism of the enzymes in oral care products has been partially elucidated. Enzymes such as lysozyme, lactoperoxidase and glucose oxidase are transferred from the tooth pastes to the pellicle. Being components of the pellicle, these enzymes are catalytically highly active.[57][58] Also, as part of tooth pastes, the lactoperoxidase system has a beneficial influence to avoid early childhood caries[59] by reducing the number of colonies formed by the cariogenic microflora while increasing the thiocyanate concentration. With xerostomia patients, tooth pastes with the lactoperoxidase system are seemingly superior to fluoride-containing tooth pastes with respect to plaque formation and gingivitis.[60] More studies are required[58] to examine further the protective mechanisms.[61]

The application of lactoperoxidase is not restricted to caries, gingivitis, and periodontitis.[62] A combination of lysozyme and lactoperoxidase can be applied to support the treatment of the burning mouth syndrome (glossodynia). In combination with lactoferrin, lactoperoxidase combats halitosis;[63] in combination with lactoferrin and lysozyme, lactoperoxidase helps to improve symptoms of xerostomia.[64] Furthermore, gels with lactoperoxidase help to improve symptoms of oral cancer when saliva production is compromised due to irradiation. In this case, also the oral bacterial flora are influenced favorably.[65][66][67]

See also

References

  1. ↑ Tenovuo JO (1985). "The peroxidase system in human secretions". The Lactoperoxidase system: chemistry and biological significance. New York: Dekker. pp. 272. ISBN 978-0-8247-7298-7. 
  2. ↑ "Biochemistry of peroxidase systems: antimicrobial effects". The Lactoperoxidase system: chemistry and biological significance. New York: Dekker. 1985. pp. 272. ISBN 978-0-8247-7298-7. 
  3. ↑ "Molecular cloning of cDNAs encoding bovine and human lactoperoxidase". DNA and Cell Biology 9 (7): 499–509. September 1990. doi:10.1089/dna.1990.9.499. PMID 2222811. 
  4. ↑ "Cloning and sequence analysis of the human salivary peroxidase-encoding cDNA". Gene 173 (2): 261–4. September 1996. doi:10.1016/0378-1119(96)00078-9. PMID 8964511. 
  5. ↑ "Interaction of lactoperoxidase with hydrogen peroxide. Formation of enzyme intermediates and generation of free radicals". Free Radical Biology & Medicine 6 (3): 323–39. 1989. doi:10.1016/0891-5849(89)90059-2. PMID 2545551. 
  6. ↑ 6.0 6.1 The Lactoperoxidase system: chemistry and biological significance. New York: Dekker. 1985. pp. 272. ISBN 978-0-8247-7298-7. 
  7. ↑ "Iodine and Selenium as Antiviral Agents: Potential Relevance to SARS-CoV-2 and Covid-19". Archives of Oral and Maxillofacial Surgery 3 (1): 69. November 2020. doi:10.36959/379/357. ISSN 2689-8772. 
  8. ↑ "Increased concentration of iodide in airway secretions is associated with reduced respiratory syncytial virus disease severity". American Journal of Respiratory Cell and Molecular Biology 50 (2): 389–97. February 2014. doi:10.1165/rcmb.2012-0529OC. PMID 24053146. 
  9. ↑ "Iodide supplementation of the anti-viral duox-lactoperoxidase activity may prevent some SARS-CoV-2 infections". European Journal of Clinical Nutrition 76 (4): 629–630. September 2021. doi:10.1038/s41430-021-00995-2. PMID 34471253. 
  10. ↑ "Peroxidase-thiocyanate-peroxide antibacterial system does not damage DNA". Antimicrobial Agents and Chemotherapy 23 (2): 267–72. February 1983. doi:10.1128/aac.23.2.267. PMID 6340603. 
  11. ↑ 11.0 11.1 11.2 "The metabolism of 17 beta-estradiol by lactoperoxidase: a possible source of oxidative stress in breast cancer". Carcinogenesis 15 (11): 2637–43. November 1994. doi:10.1093/carcin/15.11.2637. PMID 7955118. 
  12. ↑ 12.0 12.1 12.2 "Can estrogenic radicals, generated by lactoperoxidase, be involved in the molecular mechanism of breast carcinogenesis?". Redox Report 5 (4): 229–35. 2000. doi:10.1179/135100000101535672. PMID 10994878. 
  13. ↑ "Bovine carbonyl lactoperoxidase structure at 2.0Å resolution and infrared spectra as a function of pH". The Protein Journal 31 (7): 598–608. October 2012. doi:10.1007/s10930-012-9436-3. PMID 22886082. 
  14. ↑ PDB: 2r5l​; "Crystal structure of lactoperoxidase at 2.4 A resolution". Journal of Molecular Biology 376 (4): 1060–75. February 2008. doi:10.1016/j.jmb.2007.12.012. PMID 18191143. 
  15. ↑ 15.0 15.1 "Structure, functions and applications of lactoperoxidase in natural antimicrobial systems". Netherlands Milk & Dairy Journal 50: 227–244. 1996. 
  16. ↑ "The peroxidation of thiocyanate catalysed by myeloperoxidase and lactoperoxidase". Biochimica et Biophysica Acta (BBA) - Protein Structure and Molecular Enzymology 709 (2): 212–9. December 1982. doi:10.1016/0167-4838(82)90463-0. PMID 6295491. 
  17. ↑ "Lactoperoxidase-catalyzed oxidation of thiocyanate: polarographic study of the oxidation products". Biochemistry 21 (3): 562–7. February 1982. doi:10.1021/bi00532a023. PMID 7066307. 
  18. ↑ "Challenge testing the lactoperoxidase system against a range of bacteria using different activation agents". Journal of Dairy Science 91 (7): 2566–74. July 2008. doi:10.3168/jds.2007-0322. PMID 18565914. 
  19. ↑ "Susceptibility of anaerobic microorganisms to hypothiocyanite produced by lactoperoxidase". Acta Stomatologica Belgica 89 (3): 155–62. September 1992. PMID 1481764. 
  20. ↑ 20.0 20.1 "Bactericidal and cytotoxic effects of hypothiocyanite-hydrogen peroxide mixtures". Infection and Immunity 44 (3): 581–6. June 1984. doi:10.1128/IAI.44.3.581-586.1984. PMID 6724690. 
  21. ↑ "The biological significance of lactoferrin". International Journal of Tissue Reactions 5 (1): 87–96. 1983. PMID 6345430. 
  22. ↑ "Lysozyme and lactoperoxidase inhibit the adherence of Streptococcus mutans NCTC 10449 (serotype c) to saliva-treated hydroxyapatite in vitro". Caries Research 28 (6): 421–8. 1994. doi:10.1159/000262015. PMID 7850845. 
  23. ↑ Biological properties of whey components a review. Chicago, IL: American Dairy Products Institute. 2000. pp. 54. 
  24. ↑ "Topographical arrangement of membrane proteins in the intact myelin sheath. Lactoperoxidase incorproation of iodine into myelin surface proteins". The Journal of Biological Chemistry 250 (3): 1099–105. February 1975. doi:10.1016/S0021-9258(19)41895-4. PMID 1112791. 
  25. ↑ Reiter B.; Härnulv BG. "The preservation of refrigerated and uncooled milk by its natural lactoperoxidase system". Dairy Ind. Int. 47 (5): 13–19. 
  26. ↑ "Milk quality preservation by heat treatment or activation of the lactoperoxidase system in combination with refrigerated storage". Milchwissenschaft 38 (11). 1983. 
  27. ↑ "Changes in Bacteriological Quality of Raw Milk Stabilized by Activation of its Lactoperoxidase System and Stored at Different Temperatures". Journal of Food Protection 46 (12): 1065–1068. December 1983. doi:10.4315/0362-028x-46.12.1065. PMID 30921865. 
  28. ↑ "A new method for preserving raw milk: The lactoperoxidase antibacterial system". World Anim. Rev. 35: 23–29. 1980. 
  29. ↑ "Use of hydrogen peroxide detection strips to determine the extent of pasteurization in whole milk". International Journal of Dairy Technology 54 (1): 20–22. 2008. doi:10.1046/j.1471-0307.2001.00008.x. 
  30. ↑ Poulson OM, "Enzyme-containing bactericidal composition, and dental and wound treatment preparations comprising this composition", WO patent application WO1988002600, published 1988-04-21
  31. ↑ Hoogedoorn H (1985). "Activation of the salivary peroxidase system: clinical studies". The Lactoperoxidase system: chemistry and biological significance. New York: Dekker. pp. 217–228. ISBN 978-0-8247-7298-7. 
  32. ↑ Galley E, Godfrey DC, Guthrie WG, Hodgkinson DM, Linnington HL, "Antimicrobial Compositions Containing Iodide, Thiocyanate, Glucose And Glucose Oxidase", US patent 5607681, published 1997-03-04, assigned to The Boots Company PLC
  33. ↑ "Immunotoxins containing glucose oxidase and lactoperoxidase with tumoricidal properties: in vitro killing effectiveness in a mouse plasmacytoma cell model". Cancer Research 49 (20): 5497–504. October 1989. PMID 2790777. 
  34. ↑ "Induction of tumor necrosis factor and cytotoxicity by macrophages exposed to lactoperoxidase and microperoxidase". Life Sciences 47 (8): 703–9. 1990. doi:10.1016/0024-3205(90)90625-2. PMID 2402192. 
  35. ↑ "Deletion of the lactoperoxidase gene causes multisystem inflammation and tumors in mice". Scientific Reports 11 (1): 12429. 2021. doi:10.1038/s41598-021-91745-8. PMID 34127712. 
  36. ↑ "Lactoperoxidase and human airway host defense". American Journal of Respiratory Cell and Molecular Biology 29 (2): 206–12. August 2003. doi:10.1165/rcmb.2002-0152OC. PMID 12626341. 
  37. ↑ "Lactoperoxidase and hydrogen peroxide metabolism in the airway". American Journal of Respiratory and Critical Care Medicine 166 (12 Pt 2): S57-61. December 2002. doi:10.1164/rccm.2206018. PMID 12471090. 
  38. ↑ "The lactoperoxidase system links anion transport to host defense in cystic fibrosis". FEBS Letters 581 (2): 271–8. January 2007. doi:10.1016/j.febslet.2006.12.025. PMID 17204267. 
  39. ↑ "Lactoperoxidase: structural insights into the function,ligand binding and inhibition". International Journal of Biochemistry and Molecular Biology 4 (3): 108–28. September 2013. PMID 24049667. 
  40. ↑ "Hypothiocyanite ion: detection of the antimicrobial agent in human saliva". Journal of Dental Research 59 (9): 1466–72. September 1980. doi:10.1177/00220345800590090201. PMID 6931123. 
  41. ↑ "Lactoperoxidase, peroxide, thiocyanate antimicrobial system: correlation of sulfhydryl oxidation with antimicrobial action". Infection and Immunity 20 (2): 456–63. May 1978. doi:10.1128/IAI.20.2.456-463.1978. PMID 352945. 
  42. ↑ "The antioxidant role of thiocyanate in the pathogenesis of cystic fibrosis and other inflammation-related diseases". Proceedings of the National Academy of Sciences of the United States of America 106 (48): 20515–9. December 2009. doi:10.1073/pnas.0911412106. PMID 19918082. Bibcode: 2009PNAS..10620515X. 
  43. ↑ "A novel host defense system of airways is defective in cystic fibrosis". American Journal of Respiratory and Critical Care Medicine 175 (2): 174–83. January 2007. doi:10.1164/rccm.200607-1029OC. PMID 17082494. 
  44. ↑ "Thiocyanate concentration in saliva of cystic fibrosis patients". Folia Histochemica et Cytobiologica 46 (2): 245–6. 2008. doi:10.2478/v10042-008-0037-0. PMID 18519245. 
  45. ↑ "Inhibition of herpes simplex virus type 1, respiratory syncytial virus and echovirus type 11 by peroxidase-generated hypothiocyanite". Antiviral Research 26 (2): 161–71. March 1995. doi:10.1016/0166-3542(94)00073-H. PMID 7605114. 
  46. ↑ "Saliva can contribute in quick inhibition of HIV infectivity". AIDS 5 (5): 598–600. May 1991. doi:10.1097/00002030-199105000-00022. PMID 1650564. 
  47. ↑ "Susceptibility of influenza viruses to hypothiocyanite and hypoiodite produced by lactoperoxidase in a cell-free system". PLOS ONE 13 (7): e0199167. 2018. doi:10.1371/journal.pone.0199167. PMID 30044776. Bibcode: 2018PLoSO..1399167P. 
  48. ↑ "Enhancement of respiratory mucosal antiviral defenses by the oxidation of iodide". American Journal of Respiratory Cell and Molecular Biology 45 (4): 874–81. October 2011. doi:10.1165/rcmb.2010-0329OC. PMID 21441383. 
  49. ↑ "Peroxidase-mediated virucidal systems". Science 167 (3915): 195–6. January 1970. doi:10.1126/science.167.3915.195. PMID 4311694. Bibcode: 1970Sci...167..195B. 
  50. ↑ Tenovuo JO (1985). "Biochemistry of Peroxidase System: Antimicrobial Effects". The Lactoperoxidase system: chemistry and biological significance. New York: Dekker. pp. 272. ISBN 978-0-8247-7298-7. 
  51. ↑ "Sensitivity of Helicobacter pylori to an innate defence mechanism, the lactoperoxidase system, in buffer and in human whole saliva". Journal of Medical Microbiology 53 (Pt 9): 855–860. September 2004. doi:10.1099/jmm.0.45548-0. PMID 15314191. 
  52. ↑ "Antibacterial activity of hydrogen peroxide and the lactoperoxidase-hydrogen peroxide-thiocyanate system against oral streptococci". Infection and Immunity 62 (2): 529–35. February 1994. doi:10.1128/IAI.62.2.529-535.1994. PMID 8300211. 
  53. ↑ "A kinetic study on the lactoperoxidase catalyzed oxidation of estrogens". Biometals 19 (6): 587–92. December 2006. doi:10.1007/s10534-006-0002-3. PMID 16944280. 
  54. ↑ "Lactoperoxidase-catalyzed activation of carcinogenic aromatic and heterocyclic amines". Chemical Research in Toxicology 17 (12): 1659–66. December 2004. doi:10.1021/tx049787n. PMID 15606142. 
  55. ↑ "Lactoperoxidase in the prevention of plaque accumulation, gingivitis and dental caries. 3. Effect of mouthrinses with amyloglucosidase and glucoseoxidase in the model system of experimental gingivitis and caries in man". Odontologisk Revy 25 (1): 69–80. 1974. PMID 4522423. 
  56. ↑ "Clinical uses of an enzyme-containing dentifrice". Journal of Clinical Periodontology 13 (10): 950–6. November 1986. doi:10.1111/j.1600-051x.1986.tb01433.x. PMID 3098804. 
  57. ↑ "Efficacy of enzymatic toothpastes for immobilisation of protective enzymes in the in situ pellicle". Archives of Oral Biology 55 (7): 463–9. July 2010. doi:10.1016/j.archoralbio.2010.03.020. PMID 20417500. 
  58. ↑ 58.0 58.1 "Enzymes in the acquired enamel pellicle". European Journal of Oral Sciences 113 (1): 2–13. February 2005. doi:10.1111/j.1600-0722.2004.00180.x. PMID 15693823. 
  59. ↑ "Effect of lactoperoxidase system containing toothpaste on cariogenic bacteria in children with early childhood caries". The Journal of Clinical Pediatric Dentistry 33 (4): 299–303. 2009. doi:10.17796/jcpd.33.4.83331867x68w120n. PMID 19725235. 
  60. ↑ "Effect of a lactoperoxidase containing toothpaste in radiation-induced xerostomia". International Dental Journal 44 (2): 133–8. April 1994. PMID 8063434. 
  61. ↑ "Effects of a lactoperoxidase-system-containing toothpaste on dental plaque and whole saliva in vivo". Acta Odontologica Scandinavica 52 (6): 346–53. December 1994. doi:10.3109/00016359409029032. PMID 7887144. 
  62. ↑ "Different therapeutic strategies for burning mouth syndrome: preliminary data". Journal of Oral Pathology & Medicine 39 (8): 611–6. September 2010. doi:10.1111/j.1600-0714.2010.00922.x. PMID 20701667. 
  63. ↑ "Effects of a composition containing lactoferrin and lactoperoxidase on oral malodor and salivary bacteria: a randomized, double-blind, crossover, placebo-controlled clinical trial". Clinical Oral Investigations 15 (4): 485–93. August 2011. doi:10.1007/s00784-010-0422-x. PMID 20512389. 
  64. ↑ "Evaluation of the clinical efficacy of a mouthwash and oral gel containing the antimicrobial proteins lactoperoxidase, lysozyme and lactoferrin in elderly patients with dry mouth--a pilot study". Gerodontology 25 (1): 3–9. March 2008. doi:10.1111/j.1741-2358.2007.00197.x. PMID 18194332. 
  65. ↑ "Controlled study of lactoperoxidase gel on oral flora and saliva in irradiated patients with oral cancer". The Journal of Craniofacial Surgery 18 (5): 1157–64. September 2007. doi:10.1097/scs.0b013e3180de6311. PMID 17912104. 
  66. ↑ "A double-blind, crossover study of Biotène Oralbalance and BioXtra systems as salivary substitutes in patients with post-radiotherapy xerostomia". European Journal of Cancer Care 14 (4): 319–26. September 2005. doi:10.1111/j.1365-2354.2005.00587.x. PMID 16098116. 
  67. ↑ "Effectiveness of saliva substitute products in the treatment of dry mouth in the elderly: a pilot study". The Journal of the Royal Society for the Promotion of Health 125 (1): 35–41. January 2005. doi:10.1177/146642400512500113. PMID 15712851. 

Further reading

External links



Retrieved from "https://handwiki.org/wiki/index.php?title=Biology:Lactoperoxidase&oldid=3537674"