Hosiyat va funksiyai safedaho

Hosiyati safedaho. Safedaho monandi digar moddahoi gayriorganiki va organiki yak qator khosiyathoi fizikiyu khimiyavi zohir menamoyand, ki az tashkilyobii strukturai onho barmeoyad. Pesh az hama, safedaho asosan molekulahoi dar ob halshavandaand, binobar in faoliyati khudro tanho dar mahlulhoi obi zohir karda metavonand. Duyum, molekulahoi safe dagi zaryadi kaloni sathi dorand, ki on yak qator tasiroti elektrokhimiyaviro muayyan mekunad, masalan, faoliyati katalizii guzaronandagii membrana va digar amalho. Seyum, safedaho nisbat ba harorat noustuvorand, yane faoliyati khudro dar doirai haroratash kam zohir menamoyand.

Az tasiri harorati baland, inchunin, beob gardonidan, tagyiryobii rN va digar omilho strukturai safedaho vayron meshavad. Dar ibtido strukturai az hama zaif – strukturai chorumin, bad seyumin va duyumin vayron khohand shud; vayronshavii strukturai yakumin boshad, dar sharoiti beshtar shadid ba amal meoyad. Strukturai khudro gum kardani molekulai safeda denaturatsiya nomida meshavad.

Agar tagyiroti sharoiti muhit ba vayronshavii strukturai yakumini molekula ovarda narasonad, pas dar vaqti barqaror namudani sharoiti mutadili muhit strukturai safeda va faoliyati funksionalii on purra ba vujud ovarda meshavad. CHunin ravand renaturatsiya nomida shudaast.

In khosiyati safeda dar tib baroi tayyor kardani baze doruho, masalan, antibiotikho, vaksinaho, khunoba, fermentho; dar sanoati khurokvori baroi hosil namudani konsentrathoi khuroki, ki dar holati khushk muddati daroz khosiyati gizoii khudro nigoh medorand, istifoda meshavad.

Funksiyai safedaho.

Funksiyai safedaho dar hujayra nihoyat gunogun ast. YAke az muhimtarin funksiyahoi on – funksiyai plastiki (binokori) meboshad: safedaho dar kori ba vujud ovardani membrana va organoidhoi hujayra, inchunin strukturai gayrihujayravi ishtirok menamoyand. Hususan, maqomi katalizii safedaho ahamiyati kalon dorad. Hamai katalizatorhoi biologi-fermentho-moddahoi tabiatashon safedagi buda, surati reaksiyahoi khimiyaviro dar hujayraho to dahho va sadho hazor marotiba metezonand.

Oid ba in funksiyai muhimi safedaho tavaqquf namuda, onro qadre mufassal dida mebaroem. Istilohi «kataliz», ki dar khimiyai biologi nisbat ba sanoati khimiyavi kamtar duchor meoyad, aynan «kushodan», «ozod kardan»-ro mefahmonad. Moddahoe, ki ba katalizatorho mansuband, tabadduloti khimiyaviro tezonda, vale khudi onho sarf nameshavand, yane tarkibi katalizatorho pesh va bad az reaksiya tagyir nameyobad.

Mohiyati reaksiyai katalizi, qati nazar az miqdori ziyodi katalizatorhoi gunogun va navhoi reaksiyai khimiyavii dar onho ishtirok doshta az on iborat ast, ki moddahoi avvala bo katalizatorho payvastagihoi mobayni hosil menamoyand. In payvastagiho zud ba mahsuloti okhirin tabdil meyoband, vale katalizator dar namudi avvala barqaror megardad. Fermentho ham az jumlai chunin katalizatorho meboshand. Baroi onho niz hamai qonunhoi kataliz khos ast.

Ammo fermentho tabiati safedagi dorand, binobar in onho khosiyati makhsus zohir menamoyand. Dar bayni ferment ho va katalizatorhoi malumi khimiyai gayriorganiki, masalan, platina, oksidi vanadiy chi guna umumiyat va farqiyat vujud dorad? Hamon yak katalizatori gayriorganikiro dar istehsoloti gunogun istifoda burdan mumkin ast. Vale ferment faqat yak reaksiya yo yak namudi reaksiyaro metezonad, yane on nisbat ba katalizatori gayriorganiki makhsusiyati beshtar dorad (rasmi 3.3.). YAke az khosiyathoi muhimi fermentho dar organizm az hamin iborat ast.

Tasiri mutaqobilai ferment (F) bo modda (S), ki dar natija mahluli reaksiya (M) hosil meshavad F+S FS FP F+P

Malum ast, ki ba surati reaksiyahoi khimiyavi hama vaqt harorat tasir merasonad. Aksari reaksiyaho bo katalizatorhoi gayriorganiki dar harorati nihoyat baland meguzarand. Hangomi baland kardani harorat, odatan, surati reaksiyahoi khimiyavi meafzoyad. Baroi reaksiyahoi fermentativi chunin afzoish dar harorati muvofiq mahdud ast (rasmi 3.4).

Minbad baland shudani harorat ba tagyirot dar strukturai ferment (nigared ba denaturatsiyai safedaho) ovarda merasonad, faoliyati on sust shuda, sipas, qat megardad. Ammo baze fermenthoi mikroorganizmhoe, ki dar chashmahoi tabiii obashon garm yofta shudaand, na faqat ba harorati nazdik ba nuqtai jushishi ob tobovarand, balki hatto, dar chunin sharoit faoliyati behad baland zohir karda metavonand.

Baroi aksariyati fermentho harorati muvofiq nazdiki 35-400S meboshad. Reaksiyaho bo ishtiroki katalizatorhoi gayriorganiki, odatan, zeri fishori baland meguzarand, vale fermentho dar fishori mutadili atmosferi faoliyat mekunand. Farqiyati muhimi fermentho nisbat ba digar katalizatorho dar on ast, ki surati reaksiyahoe, ki fermentho metezonand, to dahho, hazorho va bazan millionho marotiba az surati reaksiyahoe, ki dar ishtiroki katalizatorhoi gayriorganiki dastras megardad, balandtar meboshad.

Ba hama malum ast, ki peroksidi gidrogen (N2O2) hamchun moddai safedkunanda va dezinfeksiyavi ba kor burda meshavad. Vay be ishtiroki katalizator bisyor sust tajziya meshavad:

Dar ishtiroki katalizatori gayriorganiki (namakhoi ohan yo dioksidi mangan) reaksiyai tajziyai peroksidi gidrogen chand marotiba zudtar meguzarad. Ammo katalaza (fermente, ki amalan dar hamai khujayraho mavjud ast), peroksidi gidrogenro bo surati nihoyat baland tajziya menamoyad: yak molekulai katalaza dar 1 daqiqa beshtar az 5 mln. molekulai peroksidi gidrogenro tajziya mekunad.

Tasiri suratnokii katalizatorho dar reaksiyahoi gunogun ba energiyai aktivatsiya (faolnoki), yane hamon energiyae, ki rasondani on ba molekulai tasirkunanda zarur ast, vobastagi dorad. Mahz ba tufayli qimati kaloni energiyai aktivatsiya-kogaz, chub, karasin va digar moddahoi suzanda dar harorati khona khud az khud darnamegirand. Agar onho dar muhiti oksigen garm karda shavand, on goh imkoniyati sukhtanashon ba amal meoyad. CHi qadar harorati muhiti atrof baland boshad, hamon qadar kamtar energiyai ilovagi sarf meshavad, to ki moddahoi suzanda alanga girand. Katalizatorhoi biologi-fermentho vazifai bo nom «garmkunanda»-ro niz ijro mekunand. In imkoniyati bemamoniat ba reaksiya dokhil shudani bisyor molekulahoro tamin menamoyad.

Funksiyai harakati organizmhoi zindaro safedahoi makhsusi kashishkhuranda tamin mekunand. In safedaho dar hamai namudhoi harakat, ki ba onho organizm va hujayraho qobiliyat dorand, ishtirok menamoyand: larzishi muyak, mijgonak, junbishi qamchinak dar soddatarinho, kashishkhurii mushakho dar hayvonoti serhujayra, harakati barg dar rastaniho va gayra.

Funksiyai naqliyotii safedaho dar payvast namudani elementhoi khimiyavi (masalan, oksigenro payvast kardani gemoglobin) yo moddahoi faoli biologi (gormonho) hamchunin rasonidani onho ba boftahoi gunogun va uzvhoi badan ifoda meyobad. Safedahoi makhsusi naqliyoti KRN-ro, ki dar yadroi hujayra sintez meshavad, ba sitoplazma meguzaronand. Maqomi safedahoi naqliyoti, khususan, dar membranahoi berunii hujayraho kalon ast: onho az muhit moddahoi gunogunro ba sitoplazma meguzaronand.

Hangomi ba organizm dohil shudani safedahoi begona yo mikroorganizmho dar zarrahoi safedi khun (leykositho) safedahoi makhsus (antitela) hosil meshavand. Onho moddahoi ba organizm begona (antigenho)-ro payvast menamoyand, ki dar natija komplekshoi bezarar va bezahr «antigen-antitela» hosil meshavand. Onho minbad bo shaklhoi digari leykositho furu kashida shuda, hazm megardand (fagositoz) va in funksiyai muhofizatii safedaho meboshad.

Safedaho yake az manbahoi energiyai hujayra meboshand, yane funksiyai energetikiro ijro menamoyand. Dar vaqti to mahsuloti okhirin purra tajziya shudani 1g safeda 17,6 k J energiya khorij megardad. Ammo dar organizm safedaho ba chunin sifat kam istifoda meshavand. Aminokislotaho, ki hangomi tajziyai molekulai safedaho ozod shudaand, dar reaksiyahoi mubodilai plastiki baroi bunyodi safedahoi nav ishtirok menamoyand.

Savolho baroi sanjish:

1. Ba tarkibi hujayra kadom moddahoi organiki dokhil meshavand?
2. Safedaho az kadom payvastagihoi soddai organiki iboratand?
3. Peptid chist? CHiro polipeptid menomand?
4. Strukturai yakumini safeda chist?
5. Strukturai duyumin, seyumin va chorumini safeda chi tavr ba vujud meoyand?
6. CHiro denaturatsiya va renaturatsiyai safeda menomand?
7. SHumo kadom funksiyai safedahoro medoned? Misolho biyored.