| 词条 | Legumain |
| 释义 |
| image = Human legumain with catalytic triad in red, bound to product in black. ({{PDB|4AW9}}) Human pro-legumain with catalytic triad in red, bound to its auto-inhibitory C-terminal prodomain in green. ({{PDB|4FGU}})| caption = | EC_number = 3.4.22.34 | CAS_number = 149371-18-6 | GO_code = | Name = Legumain | IUBMB_EC_number = 3/4/22/34 | width = 280px }}Legumain ({{EC number|3.4.22.34}}, asparaginyl endopeptidase, citvac, proteinase B, hemoglobinase, PRSC1 gene product or LGMN (Homo sapiens), vicilin peptidohydrolase, bean endopeptidase) is an enzyme that in humans is encoded by the LGMN gene (previous symbol PRSC1).[1][2][3] DistributionThis enzyme was originally identified in the vacuoles of legume seeds, and was subsequently identified the lysosomes of mammals and Schistosoma mansoni.[4] They are now known to be present in a range of plants and animals.[5][6] ActivityReaction and specificityThis enzyme catalyses the following chemical reaction: Hydrolysis of proteins and small molecule substrates at -Asn-Xaa- bonds Both plant and animal legumains are most active in acidic environments.[7][8] Prodomain processingLegmains are produced as inactive precursor zymogens. their C-terminal domain binds over their active site (where a substrate would normally bind), inhibiting activity.[7] Once in the acidic environment of the vacuole or lysosome, the prodomain is cleaved off to reveal the active enzyme.[7][8] MechanismLegumain is a cysteine protease from the C13 family of the CD clan of proteases (MEROPS).[8] It uses a catalytic triad of Cysteine-Histidine-Asparagine in its active site to perform covalent proteolysis of its substrate.[3]{{multiple image | align = left | width = 250 | image1 = Legumain active site.png | caption1 = Active site of human legumain with catalytic triad in red, bound to product in black. ({{PDB|4AW9}}) | image2 = Pro-legumain active site.png | caption2 = Active site of human legumain with catalytic triad in red, bound to its auto-inhibitory C-terminal prodomain in green. ({{PDB|4FGU}}) }} {{Clear}} References1. ^{{cite book | chapter = Asparaginyl endopeptidase | title = Handbook of Proteolytic Enzymes | vauthors = Hara-Nishimura I |year = 1998 |volume = |pages = 746–749 | veditors = Barrett AJ, Rawlings ND, Woessner JF |publisher = Academic Press |location = London }} 2. ^{{cite book | chapter = Schistosome legumain | title = Handbook of Proteolytic Enzymes | vauthors = Dalton JP, Brindley PJ |year = 1998 |volume = |pages = 749–754 | veditors = Barrett AJ, Rawlings ND, Woessner JF |publisher = Academic Press |location = London }} 3. ^1 {{cite journal | vauthors = Chen JM, Rawlings ND, Stevens RA, Barrett AJ | title = Identification of the active site of legumain links it to caspases, clostripain and gingipains in a new clan of cysteine endopeptidases | journal = FEBS Letters | volume = 441 | issue = 3 | pages = 361–5 | date = December 1998 | pmid = 9891971 | doi = 10.1016/S0014-5793(98)01574-9 }} 4. ^{{cite journal | vauthors = Chen JM, Dando PM, Rawlings ND, Brown MA, Young NE, Stevens RA, Hewitt E, Watts C, Barrett AJ | title = Cloning, isolation, and characterization of mammalian legumain, an asparaginyl endopeptidase | journal = The Journal of Biological Chemistry | volume = 272 | issue = 12 | pages = 8090–8 | date = March 1997 | pmid = 9065484 | doi = 10.1074/jbc.272.12.8090 }} 5. ^{{cite journal | vauthors = Müntz K, Shutov AD | title = Legumains and their functions in plants | language = English | journal = Trends in Plant Science | volume = 7 | issue = 8 | pages = 340–4 | date = August 2002 | pmid = 12167328 | doi = 10.1016/S1360-1385(02)02298-7 }} 6. ^{{cite journal | vauthors = Shutov AD, Blattner FR, Kakhovskaya IA, Müntz K | title = New aspects of the molecular evolution of legumains, Asn-specific cysteine proteinases | journal = Journal of Plant Physiology | volume = 169 | issue = 3 | pages = 319–21 | date = February 2012 | pmid = 22196948 | doi = 10.1016/j.jplph.2011.11.005 }} 7. ^1 2 {{cite journal | vauthors = Chen JM, Fortunato M, Barrett AJ | title = Activation of human prolegumain by cleavage at a C-terminal asparagine residue | journal = The Biochemical Journal | volume = 352 Pt 2 | issue = 2 | pages = 327–34 | date = December 2000 | pmid = 11085925 | pmc = 1221463 | doi = 10.1042/bj3520327 }} 8. ^1 2 {{Cite web|url=http://merops.sanger.ac.uk/cgi-bin/famsum?family=C13|title=C13 family|website=merops.sanger.ac.uk|publisher=MEROPS - the Peptidase Database|access-date=2016-06-09}} External links
1 : EC 3.4.22 |
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