Aspergilloglutamic peptidase, also called aspergillopepsin II (EC 3.4.23.19, proctase A, Aspergillus niger acid proteinase A, Aspergillus niger var. macrosporus aspartic proteinase) is a proteolytic enzyme.[1][2] The enzyme was previously thought be an aspartic protease, but it was later shown to be a glutamic protease with a catalytic Glu residue at the active site, and was therefore renamed aspergilloglutamic peptidase.[3]

Aspergilloglutamic peptidase
Aspergilloglutamic peptidase dimer
Identifiers
EC no.3.4.23.19
CAS no.9025-49-4
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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.[4]

This enzyme catalyses the following chemical reaction

Preferential cleavage in B chain of insulin: Asn3-Gln, Gly13-Ala, Tyr26-Thr

This enzyme is isolated from Aspergillus niger var. macrosporus.

References

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  1. ^ Chang, W.J.; Horiuchi, S.; Takahashi, K.; Yamasaki, M.; Yamada, Y. (1976). "The structure and function of acid proteases. VI. Effects of acid protease-specific inhibitors on the acid proteases from Aspergillus niger var. macrosporus". J. Biochem. 80: 975–981. PMID 12156.
  2. ^ Iio, K.; Yamasaki, M. (1976). "Specificity of acid proteinase A from Aspergillus niger var. macrosporus towards B-chain of performic acid oxidized bovine insulin". Biochim. Biophys. Acta. 429: 912–924. doi:10.1016/0005-2744(76)90336-3. PMID 1268233.
  3. ^ Takahashi K (2013). "Structure and function studies on enzymes with a catalytic carboxyl group(s): from ribonuclease T1 to carboxyl peptidases". Proc Jpn Acad Ser B Phys Biol Sci. 89 (6): 201–25. doi:10.2183/pjab.89.201. PMC 3749792. PMID 23759941.
  4. ^ Sasaki H, Kubota K, Lee WC, Ohtsuka J, Kojima M, Iwata S, Nakagawa A, Takahashi K, Tanokura M (2012). "The crystal structure of an intermediate dimer of aspergilloglutamic peptidase that mimics the enzyme-activation product complex produced upon autoproteolysis". Journal of Biochemistry. 152 (1): 45–52. doi:10.1093/jb/mvs050. PMID 22569035.
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