View source for Biology:Aspergillopepsin II

{{Infobox enzyme
| Name       = Aspergilloglutamic peptidase
| EC_number  = 3.4.23.19
| CAS_number = 9025-49-4
| GO_code    =
| image      = Aspergilloglutamic peptidase.jpg
| width      = 240px
| caption    = Aspergilloglutamic peptidase dimer 
}}
'''Aspergilloglutamic peptidase''', also called '''aspergillopepsin II''' ({{EC number|3.4.23.19}}, ''proctase A'', '' Aspergillus niger acid proteinase A'', ''Aspergillus niger var. macrosporus aspartic proteinase'') is a proteolytic [[Biology:Enzyme|enzyme]].<ref>{{cite journal | title = The structure and function of acid proteases. VI. Effects of acid protease-specific inhibitors on the acid proteases from ''Aspergillus niger'' var. macrosporus |author1 = Chang, W.J. |author2 =Horiuchi, S. |author3 =Takahashi, K. |author4 =Yamasaki, M. |author5 =Yamada, Y. |journal = J. Biochem. |year = 1976 |volume = 80 |pages = 975–981 |pmid = 12156}}</ref><ref>{{cite journal | title = Specificity of acid proteinase A from ''Aspergillus niger'' var. macrosporus towards B-chain of performic acid oxidized bovine insulin |author1 = Iio, K. |author2 =Yamasaki, M. |journal = Biochim. Biophys. Acta |year = 1976 |volume = 429 |pages = 912–924 |pmid = 1268233 |doi=10.1016/0005-2744(76)90336-3}}</ref>  The enzyme was previously thought be an [[Biology:Aspartic protease|aspartic protease]], but it was later shown to be a [[Biology:Glutamic protease|glutamic protease]] with a catalytic Glu residue at the active site, and was therefore renamed aspergilloglutamic peptidase.<ref>{{cite journal |title=Structure and function studies on enzymes with a catalytic carboxyl group(s): from ribonuclease T1 to carboxyl peptidases|author=Takahashi K |journal=Proc Jpn Acad Ser B Phys Biol Sci |year= 2013|volume=89|issue=6|pages=201–25 |doi=10.2183/pjab.89.201 |pmid=23759941 |pmc=3749792}}</ref>

Determination of its molecular structure showed it to be a unique two-chain enzyme with a light chain and a heavy chain bound non-covalently with each other.  The C-terminal region of the light chain of one molecule binds to the active site cleft of another molecule in the manner of a substrate.<ref>{{cite journal |journal= Journal of Biochemistry |year= 2012 |volume=152|issue=1|pages=45–52 | doi= 10.1093/jb/mvs050 |title=The crystal structure of an intermediate dimer of aspergilloglutamic peptidase that mimics the enzyme-activation product complex produced upon autoproteolysis |vauthors=Sasaki H, Kubota K, Lee WC, Ohtsuka J, Kojima M, Iwata S, Nakagawa A, Takahashi K, Tanokura M |pmid= 22569035}}</ref>

This enzyme [[Chemistry:Catalysis|catalyses]] the following [[Chemistry:Chemical reaction|chemical reaction]]

: Preferential cleavage in B chain of [[Biology:Insulin|insulin]]: Asn<sup>3</sup>-Gln, Gly1<sup>3</sup>-Ala, Tyr<sup>26</sup>-Thr

This enzyme is isolated from ''[[Biology:Aspergillus niger|Aspergillus niger]] var. macrosporus''.

== References ==
{{reflist}}

== External links ==
* {{MeshName|Aspergillopepsin+II}}

{{Aspartic acid proteases}}
{{Enzymes}}

[[Category:EC 3.4.23]]

{{Sourceattribution|Aspergillopepsin II}}