Lactoferrina: Diferenzas entre revisións

BothA inlactoferrina bloodtanto no plasma andsanguíneo incoma secretorynos fluidsfluídos lactoferrinsecretores canpode existexistir inen diferentes differentformas polymericpoliméricas formsque rangingvan fromdesde [[monomermonómero]]s toa [[tetramertetrámero]]s. LactoferrinA tendslactoferrina totende polymerizea bothpolimerizar tanto ''in vitro'' andcoma ''in vivo'', especiallyespecialmente ata highaltas concentrationsconcentracións.<ref Name=Sousa /> SeveralVarios authorsautores foundatoparon thatque thea dominantforma formdominante ofda lactoferrinlactoferrina inen physiologicalcondicións conditionsfisiolóxicas isé aun tetramertetrámero, withe thea razón monomermonómero:tetramertetrámero ratioé ofde 1:4 ata theconcentracións proteinde concentrationsproteína ofde 10⁻⁵ M.<ref name="Bennett">{{cite journal|author = Bennett RM, Davis J|title = Lactoferrin interacts with deoxyribonucleic acid: a preferential reactivity with double-stranded DNA and dissociation of DNA-anti-DNA complexes|journal = J. Lab. Clin. Med.|volume = 99|issue = 1|pages = 127–38|year = 1982|pmid = 6274982}}</ref><ref name="pmid6979357">{{cite journal|author = Bagby GC, Bennett RM|title = Feedback regulation of granulopoiesis: polymerization of lactoferrin abrogates its ability to inhibit CSA production|journal = Blood|volume = 60|issue = 1|pages = 108–12|year = 1982|pmid = 6979357}}</ref><ref name="pmid7762423">{{cite journal|author = Mantel C, Miyazawa K, Broxmeyer HE|title = Physical characteristics and polymerization during iron saturation of lactoferrin, a myelopoietic regulatory molecule with suppressor activity|journal = Adv. Exp. Med. Biol.|volume = 357|pages = 121–32|year = 1994|pmid = 7762423|doi =10.1007/978-1-4615-2548-6_12|series = Advances in, Experimental Medicine and Biology|isbn = 978-0-306-44734-1 }}</ref>

ItSuxeriuse isque suggestedo that theestado [[oligomeroligómero|oligomérico]] stateda oflactoferrina lactoferrinestá isdeterminado determinedpola bysúa itsconcentración concentratione andque thata [[polymerizationpolimerización]] ofda lactoferrinlactoferrina isestá stronglyfortemente affectedafectada bypola thepresenza presencede ofións Ca²⁺ ions. InEn particularconcreto, monomersos weremonómeros dominantson atdominantes concentrationsa concentracións por debaixo belowde 10⁻¹⁰−10⁻¹¹ M inen thepresenza presence ofde Ca²⁺, butpero theyconvértense converteden intotetrámeros tetramersa atconcentracións lactoferrinde lactoferrina por concentrationsriba abovede 10⁻⁹−10⁻¹⁰ M.<ref name=Bennett /><ref name="Furmanski">{{cite journal|doi = 10.1084/jem.170.2.415|author = Furmanski P, Li ZP, Fortuna MB, Swamy CV, Das MR|title = Multiple molecular forms of human lactoferrin. Identification of a class of lactoferrins that possess ribonuclease activity and lack iron-binding capacity|journal = J. Exp. Med.|volume = 170|issue = 2|pages = 415–29|year = 1989|pmid = 2754391|pmc = 2189405}}</ref> A [[Titertitulación]] ofde lactoferrinlactoferrina inno thesangue bloodcorresponde correspondsa to thisesta particular "transitionconcentración concentrationde transición" ande thusasí lactoferrina inlactoferrina thedo bloodsangue shoulddebería bepresentarse presentedtanto bothen asforma ade monomermonómero andcoma de tetramertetrámero. ManyMoitas functionalpropiedades propertiesfuncionais ofda lactoferrinlactoferrina dependdependen ondo itsseu oligomericestado stateoligomérico. InPor particularexemplo, monomerica lactoferrina monomérica, butpero notnon tetramerica lactoferrintetramérica, cané stronglya bindque tose DNAune fortemente ao [[ADN]].