Na ʻIkepili Peptide 
ʻApelila 21, 2025
ʻO nā ʻatikala a me nā ʻike huahana i hāʻawi ʻia ma kēia pūnaewele pūnaewele wale nō no ka hoʻolaha ʻana i ka ʻike a me nā kumu hoʻonaʻauao.
ʻO nā huahana i hāʻawi ʻia ma kēia pūnaewele i manaʻo wale ʻia no ka noiʻi in vitro. Hana ʻia ka noiʻi in vitro (Latin: *i ke aniani*, ʻo ia hoʻi i ka ipu aniani) ma waho o ke kino kanaka. ʻAʻole kēia mau huahana he lāʻau lapaʻau, ʻaʻole i ʻae ʻia e ka US Food and Drug Administration (FDA), a ʻaʻole pono e hoʻohana ʻia no ka pale ʻana, mālama, a hoʻōla paha i kekahi maʻi olakino, maʻi, a i ʻole maʻi. Ua pāpā loa ʻia e ke kānāwai ke hoʻokomo i kēia mau huahana i loko o ke kino kanaka a holoholona paha ma kekahi ʻano.
He aha ka Peptide Bond
ʻO ka paʻa peptide kahi paʻa covalent maʻamau i loko o nā molekele protein, i hana ʻia ma o ka hopena condensation dehydration ma waena o ka pūʻulu α-carboxyl (α-COOH) o hoʻokahi waikawa amino a me ka pūʻulu α-amino (-NH₂) o kahi waikawa amino pili. ʻO kona ʻano kemika he paʻa amide. Hoʻoholo kēia loulou i ke ʻano kumu o ka iwi kuamoʻo o ke kaulahao polypeptide: hoʻopili ʻia ka amino-terminal (N-terminal) a me ka carboxyl-terminal (C-terminal) ma o ka hana hou ʻana i nā paʻa peptide e hana i kahi kaʻina laina. Ma muli o ka hoʻokumu ʻia ʻana o kahi ʻōnaehana hoʻohui p-π ma waena o ka carbonyl carbon (C=O) a me imino nitrogen (-NH-) i loko o ka paʻa peptide, hōʻike ka palapala CN i nā ʻano ʻāpana paʻa pālua, e hāʻawi ana i ka mokulele paʻa peptide me nā hiʻohiʻona coplanar paʻa. Hāʻawi kēia i nā kaohi hoʻolālā koʻikoʻi no ka pelu ʻana i nā ʻōnaehana protein kiʻekiʻe.
Mechanism of Peptide Bond Biosynthesis
Hoʻokumu ʻia ka peptide bond synthesis i loko o nā ribosomes, e hilinaʻi ana i ka RNA transfer (tRNA) e lawe i nā waikawa amino. Ma o ka hui ʻana o nā anticodons ma ka tRNA me nā codons ma ka messenger RNA (mRNA), hoʻonoho ʻia nā amino acids ma ka pae P a me kahi pae o ka ribosome. ʻO ka pūʻulu amino o ka ʻakika amino ma ka pūnaewele A e hoʻoheheʻe ʻia me ka hui carboxyl o ka ʻakika amino ma ka pūnaewele P, e hana ana i kahi paʻa amide (-CO-NH-) a hoʻokuʻu i kahi mole wai. Ke neʻe nei ka ribosome ma ka mRNA, e koi ana i ke kaulahao peptide e hoʻonui mai ka N-terminal a i ka C-terminal. Hoʻohana ʻia kēia kaʻina hana e GTP, me ke kauoha o ka pilina amino acid i hoʻomalu pono ʻia e nā codons e hoʻokō i ka hui kuhikuhi o ke kaulahao polypeptide.
Nā hiʻohiʻona hoʻolālā Spatial a me nā waiwai kino o nā Peptide Bonds
Hoʻoholo ka hoʻolālā conjugated planar o ka paʻa peptide i kāna conformation spatial kūʻokoʻa: ʻo ka carbonyl oxygen a me ka hydrogen amino i loko o kahi hoʻonohonoho trans, e hana ana i kahi kihi paʻa ma kahi o 120 °, ʻo ia kahi ʻāpana planar paʻa (ʻo ke kihi dihedral ω kokoke i 180 °). Hoʻopaʻa kēia hiʻohiʻona i nā degere o ke kūʻokoʻa o nā kihi dihedral (φ a me ψ) o nā α-carbons e pili ana, e hāpai ana i ka hoʻokumu ʻana i nā ʻāpana hana lua maʻamau i ke kaulahao polypeptide (e like me nā α-helice, β-sheets, a i ʻole β-huli). Ma ke ʻano o nā waiwai physicochemical, hiki i ka hui amide o ka paʻa peptide ke hana ma ke ʻano he hāʻawi hydrogen bond (amino hydrogen) a me ka ʻae (carbonyl oxygen), e komo pū ana i ke kūkulu ʻana i nā ʻoihana paʻa hydrogen i loko o nā protein a ma waena o nā mole. Hōʻike kona ʻōnaehana conjugated i ka absorption hiʻohiʻona o ke kukui ultraviolet ma nā lōʻihi hawewe o 210–230 nm, e hiki ai ke helu ʻia o ka ʻike protein e ka spectrophotometry ultraviolet. Hoʻohui ʻia, ʻo ka paʻa paʻa o ka paʻa peptide he mea paʻakikī ke hana i ka hydrolysis spontaneous i nā ʻano wai wai kūlohelohe, akā hiki ke hoʻokaʻawale ʻia ma lalo o ka catalysis o nā protease, e lawelawe ana ma ke ʻano he kī nui no ka hoʻohaʻahaʻa ʻana i ka protein intracellular.
Nā Hana Ola Ola a me nā Hoʻohana ʻenehana o nā Peptide Bonds
Ma nā hana ola, mālama ke koena ikaika o nā paʻa peptide i ka homeostasis proteome: ma kekahi ʻaoʻao, ʻo ka paʻa o kā lākou covalent linkages e hōʻoia i ka pono hana o nā macromolecules biological e like me nā enzymes a me nā protein structural; ma ka ʻaoʻao ʻē aʻe, ʻike ʻia nā paʻa peptide kikoʻī a hydrolyzed e nā proteases (e like me ka proteasome i loko o ka ʻōnaehana ubiquitin-proteasome a me nā enzyme lysosomal), e hiki ai i ka hoʻomaʻemaʻe ʻana i nā protein abnormal a me ka hoʻoponopono kino o nā molekala hōʻailona. Ma ke kahua o ka biotechnology, hoʻohana nui ʻia nā waiwai kemika o nā paʻa peptide i ka synthesis polypeptide: i ka synthesis solid-phase, hoʻohana ʻia nā hoʻolālā pūʻulu pale e koho i nā pūʻulu carboxyl o nā amino acids no ka hoʻokumu ʻana i ka pilina peptide kuhikuhi. Hoʻohana nā ʻenehana hoʻokaʻina protein i ka phenyl isothiocyanate e hana me ka N-terminal amino acid a koho koho i ka palapala peptide mua, e hiki ai i ka nānā ʻana o ke kaʻina. Eia kekahi, ua hoʻomohala ʻia nā mea hoʻopaʻa protease e pili ana i ka peptide bond analogs e kāohi i nā kikowaena ikaika o nā enzymes ma ka hoʻohālikelike ʻana i ka conformation o nā paʻa peptide kūlohelohe, e lilo i hoʻolālā koʻikoʻi i ka hoʻolālā lāʻau. Ke hoʻomau nei nā haʻawina hohonu e pili ana i ka pilina hana-hana o nā paʻa peptide e hoʻokau i nā hana ʻenehana i ka ʻenekinia protein, ka hoʻomohala ʻana i ka lāʻau polypeptide, a me ka biology synthetic.
