I-Hemoglobin (Hb) yi-metalloprotein equlathe isinyithi efumaneka kakhulu kwiiseli ezibomvu zegazi phantse kuzo zonke izilwanyana ezinethambo lomqolo. Idla ngokubizwa ngokuba "yimolekyuli exhasa ubomi" ngenxa yendima yayo ebalulekileyo ekuphefumleni. Le protein intsonkothileyo inoxanduva lomsebenzi obalulekileyo wokuthutha ioksijini ukusuka emiphungeni ukuya kuzo zonke izicwili zomzimba kunye nokwenza kube lula ukubuya kwekhabhoni diokside ukuze ikhutshwe. Ukuqonda umsebenzi wayo, iindlela ezintle ezilawula ukuziphatha kwayo, kunye nokubaluleka okukhulu kokulinganisa kwayo kwezonyango kunika ithuba lokujonga impilo yabantu kunye nezifo.

Umsebenzi kunye neNdlela yokusebenza: Umsebenzi woBugcisa boBunjineli beeMolekyuli

Umsebenzi oyintloko we-hemoglobin kukuthutha igesi. Nangona kunjalo, ayiwenzi lo msebenzi njengesiponji esilula nesingenamsebenzi. Ukusebenza kwayo kakuhle kuvela kuyilo oluntsonkothileyo lwesakhiwo kunye neendlela zokulawula ezinamandla.

Ulwakhiwo lweMolekyuli: IHemoglobin yi-tetramer, eyenziwe ziitsheyini ezine zeproteni yeglobin (ii-alpha ezimbini kunye nee-beta ezimbini kubantu abadala). Itsheyini nganye inxulunyaniswa neqela le-heme, isakhiwo sendandatho esintsonkothileyo esine-atom yesinyithi ephakathi (iFe²⁺). Le atom yesinyithi yindawo yokubopha yemolekyuli yeoksijini (O₂). Imolekyuli enye yehemoglobin ke ngoko inokuthwala iimolekyuli ezine zeoksijini.

Ukubopha Okusebenzisanayo kunye neSigmoidal Curve: Le yeyona nto ibalulekileyo ekusebenzeni kakuhle kwe-hemoglobin. Xa imolekyuli yokuqala ye-oksijini ibopha kwiqela le-heme emiphungeni (apho uxinzelelo lwe-oksijini luphezulu), ibangela utshintsho kwisakhiwo se-hemoglobin yonke. Olu tshintsho lwenza kube lula ukuba iimolekyuli ezimbini ze-oksijini ezilandelayo zibophane. Imolekyuli yesine yokugqibela ye-oksijini ibophana ngokulula kakhulu. Olu nxibelelwano "olusebenzisanayo" luphumela kwi-characteristic sigmoidal (emile okwe-S) oxygen dissociation curve. Olu hlobo lwe-S lubalulekile—oko kuthetha ukuba kwindawo etyebileyo kwi-oksijini emiphungeni, i-hemoglobin iyagcwala ngokukhawuleza, kodwa kwizicubu ezingena-oksijini, inokukhupha inani elikhulu le-oksijini ngokuncipha okuncinci koxinzelelo.

Ulawulo lwe-Allosteric: Ukusondela kwe-hemoglobin kwi-oksijini akulunganga; kulungelelaniswe kakuhle neemfuno ze-metabolic zezicubu. Oku kufezekiswa ngokusebenzisa ii-allosteric effectors:

Isiphumo seBohr: Kwizicwili ezisebenzayo, umsebenzi ophezulu we-metabolic uvelisa i-carbon dioxide (CO₂) kunye ne-asidi (H⁺ ions). I-hemoglobin iyayibona le meko yeekhemikhali kwaye iphendula ngokunciphisa ukunamathela kwayo kwioksijini, nto leyo ebangela ukukhululwa okukhulu kwe-O₂ kanye apho ifuneka khona kakhulu.

I-2,3-Bisphosphoglycerate (2,3-BPG): Le khompawundi, eveliswa kwiiseli ezibomvu zegazi, ibopha kwi-hemoglobin kwaye izinzise imeko yayo yokungabi nomoya-mpilo, nto leyo ekhuthaza ngakumbi ukukhululwa kwe-oksijini. Amanqanaba e-2,3-BPG ayanda kwiimeko ezingapheliyo ze-hypoxic, njengakwiindawo eziphakamileyo, ukuphucula ukuhanjiswa kwe-oksijini.

Ukuthuthwa kweCarbon Dioxide: IHemoglobin ikwadlala indima ebalulekileyo ekuthuthweni kweCO₂. Inxalenye encinci kodwa ebalulekileyo yeCO₂ ibopha ngokuthe ngqo kwiitsheyini zeglobin, yenze i-carbaminohemoglobin. Ngaphezu koko, ngokubopha ii-H⁺ions, i-hemoglobin yenza kube lula ukuthuthwa kwe-CO₂ eninzi njenge-bicarbonate (HCO₃⁻) kwi-plasma.

Ukubaluleka Okubalulekileyo Kovavanyo lweHemoglobin

Njengoko i-hemoglobin idlala indima ephambili, ukulinganisa ubungakanani bayo kunye nokuvavanya umgangatho wayo yintsika ebalulekileyo yezonyango zanamhlanje. Uvavanyo lwe-hemoglobin, oludla ngokuba yinxalenye ye-Complete Blood Count (CBC), lolunye lophando oluqhelekileyo lweklinikhi. Ukubaluleka kwayo akunakugqithiswa ngenxa yezi zizathu zilandelayo:

Ukubeka esweni ukuqhubela phambili kwesifo kunye nonyango:

Kwizigulane ezifunyaniswe zine-anemia, ukulinganisa i-hemoglobin ngokulandelelana kubalulekile ukujonga ukusebenza kakuhle konyango, njengokongeza isinyithi, kunye nokulandelela ukuqhubela phambili kwezifo ezingapheliyo ezisisiseko ezifana nokusilela kwezintso okanye umhlaza.

Ukufunyanwa kweHemoglobinopathy:

Uvavanyo lwe-hemoglobin olukhethekileyo, olufana ne-hemoglobin electrophoresis, lusetyenziselwa ukuxilonga izifo zemfuza ezizuzwe njengelifa ezichaphazela isakhiwo okanye imveliso ye-hemoglobin. Imizekelo eqhelekileyo yiSickle Cell Disease (ebangelwa yi-HbS variant ephosakeleyo) kunye neThalassemia. Ukufunyanwa kwangoko kubalulekile kulawulo kunye neengcebiso zemfuza.

Uvavanyo lwePolycythemia:

Inqanaba eliphezulu kakhulu le-hemoglobin linokubonisa i-polycythemia, imeko apho umzimba uvelisa iiseli ezibomvu zegazi ezininzi kakhulu. Oku kungaba yingxaki ephambili yomongo wethambo okanye impendulo yesibini kwi-hypoxia engapheliyo (umz., kwisifo semiphunga okanye kwiindawo eziphakamileyo), kwaye inomngcipheko we-thrombosis.

Uvavanyo kunye noVavanyo lweMpilo Jikelele: Uvavanyo lwe-hemoglobin luyinxalenye eqhelekileyo yokhathalelo lwangaphambi kokukhulelwa, uvavanyo lwangaphambi kotyando, kunye novavanyo lwempilo jikelele. Lusebenza njengophawu olubanzi lwempilo iyonke kunye nemeko yesondlo.

Ulawulo lweSifo seswekile: Nangona ingelona i-hemoglobin eqhelekileyo, uvavanyo lweGlycated Hemoglobin (HbA1c) lulinganisa ukuba ingakanani i-glucose enamathele kwi-hemoglobin. Lubonisa amanqanaba aqhelekileyo eswekile egazini kwiinyanga ezi-2-3 ezidlulileyo kwaye luyindlela efanelekileyo yokulawula i-glycemic yexesha elide kwizigulana ezinesifo seswekile.

Isiphelo

I-Hemoglobin ingaphezulu kakhulu kunesithwali seoksijini esilula. Yisixhobo semolekyuli esiyilwe kakuhle, esisebenzisa ukubopha ngokubambisana kunye nolawulo lwe-allosteric ukuphucula ukuhanjiswa kweoksijini ngokuphendula kwiimfuno zomzimba eziguqukayo. Ngenxa yoko, ukulinganiswa kwe-hemoglobin kwiklinikhi akusiyo nje inombolo ekwingxelo yelebhu; sisixhobo esinamandla, esingangenisi uvalelo kunye nokubeka iliso. Ibonelela ngemifanekiso ecacileyo yempilo yomntu kunye nempilo iyonke, evumela ukuchongwa kweemeko ezitshintsha ubomi, ukujongwa kwezifo ezingapheliyo, kunye nokugcinwa kwempilo yoluntu. Ukuqonda zombini ubuchule bayo bebhayoloji kunye nokubaluleka kwayo kweklinikhi kugxininisa isizathu sokuba le proteni ithobekileyo isalokhu isisiseko sesayensi ye-physiological kunye nezonyango.