PHYTEPSIN

Phytepsin ( EC 3.4.23.40) is an enzyme.^[1]^[2]^[3]^[4] This enzyme catalyses the following chemical reaction

Prefers hydrophobic residues Phe, Val, Ile, Leu, and Ala at P1 and P1', but also cleaves -Phe-Asp- and -Asp-Asp- bonds in 2S albumin from plant seeds

This enzyme is present in barley grain and other plants. It is an aspartic protease with a plant-specific insert.

References

^ Runeberg-Roos P, Törmäkangas K, Ostman A (December 1991). "Primary structure of a barley-grain aspartic proteinase. A plant aspartic proteinase resembling mammalian cathepsin D". European Journal of Biochemistry. 202 (3): 1021–7. doi: 10.1111/j.1432-1033.1991.tb16465.x. PMID 1722454.
^ Kervinen J, Sarkkinen P, Kalkkinen N, Mikola L, Saarma M (March 1993). "Hydrolytic specificity of the barley grain aspartic proteinase". Phytochemistry. 32 (4): 799–803. doi: 10.1016/0031-9422(93)85208-9. PMID 7763475.
^ Asakura T, Watanabe H, Abe K, Arai S (August 1995). "Rice aspartic proteinase, oryzasin, expressed during seed ripening and germination, has a gene organization distinct from those of animal and microbial aspartic proteinases". European Journal of Biochemistry. 232 (1): 77–83. doi: 10.1111/j.1432-1033.1995.tb20783.x. PMID 7556174.
^ Kervinen J, Törmäkangas K, Runeberg-Roos P, Guruprasad K, Blundell T, Teeri TH (1995). "Structure and possible function of aspartic proteinases in barley and other plants". Advances in Experimental Medicine and Biology. 362: 241–54. doi: 10.1007/978-1-4615-1871-6_28. ISBN 978-1-4613-5761-2. PMID 8540324. {{ cite journal}}: Cite journal requires |journal= ( help)

Phytepsin at the U.S. National Library of Medicine Medical Subject Headings (MeSH)

v t e Proteases: aspartate proteases ( EC 3.4.23)
Vertebrate	Pepsin Chymosin Renin Signal peptide peptidase Beta secretase 1 2
Pathogenic	Plasmepsin HIV-1 protease
Plant	Nepenthesin
Cathepsin	D E

v t e Enzymes
Activity	Active site Binding site Catalytic triad Oxyanion hole Enzyme promiscuity Diffusion-limited enzyme Cofactor Enzyme catalysis
Regulation	Allosteric regulation Cooperativity Enzyme inhibitor Enzyme activator
Classification	EC number Enzyme superfamily Enzyme family List of enzymes
Kinetics	Enzyme kinetics Eadie–Hofstee diagram Hanes–Woolf plot Lineweaver–Burk plot Michaelis–Menten kinetics
Types	EC1 Oxidoreductases ( list) EC2 Transferases ( list) EC3 Hydrolases ( list) EC4 Lyases ( list) EC5 Isomerases ( list) EC6 Ligases ( list) EC7 Translocases ( list)

v t e Proteases: aspartate proteases ( EC 3.4.23)
Vertebrate	Pepsin Chymosin Renin Signal peptide peptidase Beta secretase 1 2
Pathogenic	Plasmepsin HIV-1 protease
Plant	Nepenthesin
Cathepsin	D E

v t e Enzymes
Activity	Active site Binding site Catalytic triad Oxyanion hole Enzyme promiscuity Diffusion-limited enzyme Cofactor Enzyme catalysis
Regulation	Allosteric regulation Cooperativity Enzyme inhibitor Enzyme activator
Classification	EC number Enzyme superfamily Enzyme family List of enzymes
Kinetics	Enzyme kinetics Eadie–Hofstee diagram Hanes–Woolf plot Lineweaver–Burk plot Michaelis–Menten kinetics
Types	EC1 Oxidoreductases ( list) EC2 Transferases ( list) EC3 Hydrolases ( list) EC4 Lyases ( list) EC5 Isomerases ( list) EC6 Ligases ( list) EC7 Translocases ( list)