Pitrilysin

{{Short description|Class of enzymes}}

{{Infobox enzyme

| Name = Pitrilysin

| EC_number = 3.4.24.55

| CAS_number = 81611-78-1

| GO_code =

| image =

| width =

| caption =

}}

Pitrilysin ({{EC number|3.4.24.55}}, Escherichia coli protease III, protease Pi, proteinase Pi, PTR, Escherichia coli metalloproteinase Pi) is an enzyme.{{cite journal | vauthors = Finch PW, Wilson RE, Brown K, Hickson ID, Emmerson PT | title = Complete nucleotide sequence of the Escherichia coli ptr gene encoding protease III | journal = Nucleic Acids Research | volume = 14 | issue = 19 | pages = 7695–703 | date = October 1986 | pmid = 3534791 | pmc = 311789 | doi = 10.1093/nar/14.19.7695 }}{{cite journal | vauthors = Affholter JA, Fried VA, Roth RA | title = Human insulin-degrading enzyme shares structural and functional homologies with E. coli protease III | journal = Science | volume = 242 | issue = 4884 | pages = 1415–8 | date = December 1988 | pmid = 3059494 | doi = 10.1126/science.3059494 | bibcode = 1988Sci...242.1415A | doi-access = }}{{cite journal | vauthors = Becker AB, Roth RA | title = An unusual active site identified in a family of zinc metalloendopeptidases | journal = Proceedings of the National Academy of Sciences of the United States of America | volume = 89 | issue = 9 | pages = 3835–9 | date = May 1992 | pmid = 1570301 | pmc = 525585 | doi = 10.1073/pnas.89.9.3835 | bibcode = 1992PNAS...89.3835B | doi-access = free }}{{cite journal | vauthors = Ding L, Becker AB, Suzuki A, Roth RA | title = Comparison of the enzymatic and biochemical properties of human insulin-degrading enzyme and Escherichia coli protease III | journal = The Journal of Biological Chemistry | volume = 267 | issue = 4 | pages = 2414–20 | date = February 1992 | doi = 10.1016/S0021-9258(18)45895-4 | pmid = 1733942 | doi-access = free }}{{cite journal | vauthors = Anastasi A, Knight CG, Barrett AJ | title = Characterization of the bacterial metalloendopeptidase pitrilysin by use of a continuous fluorescence assay | journal = The Biochemical Journal | volume = 290 ( Pt 2) | pages = 601–7 | date = March 1993 | issue = 2 | pmid = 7680857 | pmc = 1132317 | doi = 10.1042/bj2900601 }} This enzyme catalyses the following chemical reaction:

: Preferential cleavage of -Tyr¹⁶- Leu- and -Phe²⁵- Tyr-bonds of oxidized insulin B chain. Also acts on other substrates of less than 7 kDa such as glucagon

This enzyme is present in bacteria Escherichia coli.