Pepsin: Perbedaan antara revisi
Konten dihapus Konten ditambahkan
+ Pada refluks laringofaring |
+ penyimpanan, inhibitor, dan gen |
||
Baris 54:
Pepsin dalam spesimen saluran napas dianggap sebagai penanda sensitif dan spesifik untuk refluks laringofaring.<ref name="pmid16094128">{{cite journal | vauthors = Knight J, Lively MO, Johnston N, Dettmar PW, Koufman JA | title = Sensitive pepsin immunoassay for detection of laryngopharyngeal reflux | journal = The Laryngoscope | volume = 115 | issue = 8 | pages = 1473–8 | date = Agustus 2005 | pmid = 16094128 | doi = 10.1097/01.mlg.0000172043.51871.d9 }}</ref><ref name="pmid20392035">{{cite journal | vauthors = Samuels TL, Johnston N | title = Pepsin as a marker of extraesophageal reflux | journal = The Annals of Otology, Rhinology, and Laryngology | volume = 119 | issue = 3 | pages = 203–8 | date = Maret 2010 | pmid = 20392035 | doi = }}</ref> Penelitian yang mengembangkan alat terapi terapeutik dan diagnostik pepsin baru untuk refluks lambung sedang berlangsung. Diagnosis pepsin tak invasif cepat yang disebut Peptest sekarang tersedia untuk menentukan adanya pepsin dalam sampel air liur.<ref>{{cite journal | vauthors = Bardhan KD, Strugala V, Dettmar PW | title = Reflux revisited: advancing the role of pepsin | journal = International Journal of Otolaryngology | volume = 2012 | pages = 1 | year = 2012 | pmid = 22242022 | pmc = 3216344 | doi = 10.1155/2012/646901 | url = http://www.hindawi.com/journals/ijoto/2012/646901/ }}</ref>
== Penyimpanan ==
Pepsin sebaiknya disimpan pada temperatur sangat rendah (antara −80 °C hingga −20 °C) untuk mencegah autolisis (pencernaan sendiri).
== Inhibitor ==
Pepsin dapat dihambat oleh pH tinggi atau oleh senyawa inhibitor. [[Pepstatin]] adalah senyawa dengan berat molekul rendah dan inhibitor potensial yang spesifik untuk protease asam dengan Ki sekitar 10<sup>-10</sup> M untuk pepsin. Residu statil pada pepstatin dianggap bertanggung jawab atas inhibisi pepstatin pada pepsin; [[statin]] merupakan analog potensial dari keadaan transisi untuk katalisis oleh pepsin dan protease asam lainnya. Pepstatin tidak secara kovalen mengikat pepsin sehingga penghambatan pepsin oleh pepstatin reversibel.<ref name="pmid339690">{{cite journal | vauthors = Marciniszyn J, Hartsuck JA, Tang J | title = Pepstatin inhibition mechanism | journal = Advances in Experimental Medicine and Biology | volume = 95 | issue = | pages = 199–210 | year = 1977 | pmid = 339690 | doi = 10.1007/978-1-4757-0719-9_12 }}</ref> 1-bis(diazoasetil)-2-feniletana secara reversibel menginaktivasi pepsin pada pH 5, suatu reaksi yang dipercepat dengan adanya Cu(II).<ref name="pmid4941985">{{cite journal | vauthors = Husain SS, Ferguson JB, Fruton JS | title = Bifunctional inhibitors of pepsin | journal = Proceedings of the National Academy of Sciences of the United States of America | volume = 68 | issue = 11 | pages = 2765–8 | date = November 1971 | pmid = 4941985 | pmc = 389520 | doi = 10.1073/pnas.68.11.2765 | bibcode = 1971PNAS...68.2765H }}</ref> Sukralfat juga menginhibisi pepsin.
Pepsin juga mengalami inhibisi umpan balik; produk pencernaan protein memperlambat reaksi dengan menghambat pepsin.<ref name="Northrop_1932">{{cite journal | vauthors = Northrop HJ | title = The story of the isolation of crystalline pepsin and trypsin | journal = The Scientific Monthly | year = 1932 | volume = 35 | issue = 4 | pages = 333–340 | bibcode = 1932SciMo..35..333N }}</ref><ref name="pmid4897199">{{cite journal | vauthors = Greenwell P, Knowles JR, Sharp H | title = The inhibition of pepsin-catalysed reactions by products and product analogues. Kinetic evidence for ordered release of products | journal = The Biochemical Journal | volume = 113 | issue = 2 | pages = 363–8 | date = Juni 1969 | pmid = 4897199 | pmc = 1184643 | doi = }}</ref>
== Gen ==
Tiga gen berikut mengkodekan enzim pepsinogen A manusia yang identik:
{{col-begin|width=auto}}
{{col-break}}
{{infobox protein
| Name = pepsinogen 3, kelompok I (pepsinogen A)
| caption =
| image =
| width =
| HGNCid = 8885
| Symbol = PGA3
| AltSymbols =
| EntrezGene = 643834
| OMIM = 169710
| RefSeq = NM_001079807
| UniProt = P00790
| PDB =
| ECnumber = 3.4.23.1
| Chromosome = 11
| Arm = q
| Band = 13
| LocusSupplementaryData =
}}
{{col-break}}
{{infobox protein
| Name = pepsinogen 4, kelompok I (pepsinogen A)
| caption =
| image =
| width =
| HGNCid = 8886
| Symbol = PGA4
| AltSymbols =
| EntrezGene = 643847
| OMIM = 169720
| RefSeq = NM_001079808
| UniProt = P00790
| PDB =
| ECnumber = 3.4.23.1
| Chromosome = 11
| Arm = q
| Band = 13
| LocusSupplementaryData =
}}
{{col-break}}
{{infobox protein
| Name = [[PGA5|pepsinogen 5, kelompok I (pepsinogen A)]]
| caption =
| image =
| width =
| HGNCid = 8887
| Symbol = [[PGA5]]
| AltSymbols =
| EntrezGene = 5222
| OMIM = 169730
| RefSeq = NM_014224
| UniProt = P00790
| PDB =
| ECnumber = 3.4.23.1
| Chromosome = 11
| Arm = q
| Band = 13
| LocusSupplementaryData =
}}
{{col-end}}
Gen manusia keempat mengkodekan gastriksin yabg juga dikenal sebagai pepsinogen C:
{{col-begin|width=auto}}
{{col-break}}
{{infobox protein
| Name = [[gastriksin|progastriksin<br/>(pepsinogen C)]]
| caption =
| image =
| width =
| HGNCid = 8890
| Symbol = [[gastriksin|PGC]]
| AltSymbols =
| EntrezGene = 5225
| OMIM = 169740
| RefSeq = NM_001166424
| UniProt = P20142
| PDB =
| ECnumber = 3.4.23.3
| Chromosome = 6
| Arm = p
| Band = ter
| LocusSupplementaryData = -p21.1
}}
{{col-end}}
== Referensi ==
| |||