| Sažetak | Proteini su makromolekule sastavljene od 20 standardnih aminokiselina, od čega su 9
esencijalne. Aminokiseline se u proteinu međusobno povezuju kovalentnim peptidnim vezama.
Sekvenca aminokiselina u proteinu nastaje prijepisom kodiranog genetičkog niza, transkripcijom
iz DNA te preko translacije sa RNA. Polipeptidni lanac u nativnom obliku ima određenu razinu
strukture, koja može biti: primarna, sekundarna, tercijarna i kvartarna struktura. Funkcije su
mnoge i proizlaze iz aminokiselinskog sastava te kompleksnosti strukture. Sudjeluju u
skladištenju (albumin), izgradnji (kolagen), transportu (hemoglobin), katalizi (enzimi), funkciji
mišićne kontrakcije (miozin), imunološkoj obrani tijela (antitijela), signalnoj funkciji (inzulin),
regulatornoj funkciji (PKA), te ostalim specifičnim funkcijama organizma. Pri tome je bitno
održavati stalni promet proteina radi održavanja homeostaze. Proteini evoluiraju kroz izmjene u
primaranim strukturama. Praćenjem homolognosti sekvenci unutar proteina i izradom
filogenetičkog stabla moguće je pratiti razvojni evolucijski slijed organizma. Zaključak je da su
proteini bitne makromolekule živog svijeta, ne samo zbog prehrane, rasta i razvoja nego i zbog
očuvanja svih pratećih procesa u kojima sudjeluju, budući da njihovom degradacijom dolazi do
kako ubrzanog procesa starenja tako i do smrti organizma. |
| Sažetak (engleski) | Proteins are macromolecules composed of 20 standard amino acids, of which 9 are
essential, and which are connected to each other by covalent peptide bonds. The sequence of
amino acids in protein is formed by transcription of the coded genetic sequence from DNA and
through translation via RNA. The polypeptide chain in its native form has a certain level of
structure, which can be: primary, secondary, tertiary and quaternary structure. Protein functions
are many and derive from the amino acid composition and the complexity of the structure.
Proteins participate in storage (albumin), building (collagen), transport (hemoglobin), catalytic
reactions (enzymes), muscle contraction function (myosin), immune function (antibodies),
signaling function (insulin), regulatory function (PKA), and other specific functions of organism.
In doing so, it is important to maintain a constant protein turnover rate in order to maintain
homeostasis. Proteins evolve through changes in primary structures. By monitoring sequence
homology within proteins and creating a phylogenetic tree, it is possible to monitor the
evolutionary history of an organism. The conclusion is that proteins are essential macromolecules
of the living world, not only for nutrition, growth and development, but also for the preservation
of all accompanying processes in which they participate, since their degradation leads to an
accelerated aging process and cell death. |
