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Event: 1720

Key Event Title

A descriptive phrase which defines a discrete biological change that can be measured. More help

Trypsin inhibition

Short name

The KE short name should be a reasonable abbreviation of the KE title and is used in labelling this object throughout the AOP-Wiki. More help

Inhibition, trypsin

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Biological Context

Structured terms, selected from a drop-down menu, are used to identify the level of biological organization for each KE. More help

Level of Biological Organization
Molecular

Cell term

The location/biological environment in which the event takes place.The biological context describes the location/biological environment in which the event takes place. For molecular/cellular events this would include the cellular context (if known), organ context, and species/life stage/sex for which the event is relevant. For tissue/organ events cellular context is not applicable. For individual/population events, the organ context is not applicable. Further information on Event Components and Biological Context may be viewed on the attached pdf. More help

Organ term

Key Event Components

The KE, as defined by a set structured ontology terms consisting of a biological process, object, and action with each term originating from one of 14 biological ontologies (Ives, et al., 2017; https://aopwiki.org/info_pages/2/info_linked_pages/7#List). Biological process describes dynamics of the underlying biological system (e.g., receptor signalling).Biological process describes dynamics of the underlying biological system (e.g., receptor signaling). The biological object is the subject of the perturbation (e.g., a specific biological receptor that is activated or inhibited). Action represents the direction of perturbation of this system (generally increased or decreased; e.g., ‘decreased’ in the case of a receptor that is inhibited to indicate a decrease in the signaling by that receptor). Note that when editing Event Components, clicking an existing Event Component from the Suggestions menu will autopopulate these fields, along with their source ID and description. To clear any fields before submitting the event component, use the 'Clear process,' 'Clear object,' or 'Clear action' buttons. If a desired term does not exist, a new term request may be made via Term Requests. Event components may not be edited; to edit an event component, remove the existing event component and create a new one using the terms that you wish to add. Further information on Event Components and Biological Context may be viewed on the attached pdf. More help

Key Event Overview

AOPs Including This Key Event

All of the AOPs that are linked to this KE will automatically be listed in this subsection. This table can be particularly useful for derivation of AOP networks including the KE.Clicking on the name of the AOP will bring you to the individual page for that AOP. More help

AOP Name	Role of event in AOP	Point of Contact	Author Status	OECD Status
TI-induced AC tumors	MolecularInitiatingEvent	Shigeru Hisada (send email)	Under development: Not open for comment. Do not cite	Under Development

Taxonomic Applicability

Latin or common names of a species or broader taxonomic grouping (e.g., class, order, family) that help to define the biological applicability domain of the KE.In many cases, individual species identified in these structured fields will be those for which the strongest evidence used in constructing the AOP was available in relation to this KE. More help

Term	Scientific Term	Evidence	Link
Homo sapiens	Homo sapiens	High	NCBI
Mus musculus	Mus musculus	High	NCBI
Rattus norvegicus	Rattus norvegicus	High	NCBI
Macaca fascicularis	Macaca fascicularis	High	NCBI

Life Stages

An indication of the the relevant life stage(s) for this KE. More help

Life stage	Evidence
All life stages	High

Sex Applicability

An indication of the the relevant sex for this KE. More help

Term	Evidence
Mixed	High

Key Event Description

A description of the biological state being observed or measured, the biological compartment in which it is measured, and its general role in the biology should be provided. More help

Trypsin is a digestive enzyme secreted by pancreatic acinar cells that cleaves peptide bonds at the carboxyl end of basic amino acids (lysine and arginine). Acinar cells secrete trypsinogen, the inactive form of trypsin, into the lumen of the duodenum; in turn, trypsinogen is auto-hydrolyzed by enterokinase into β-trypsin, composed of an uncleaved single chain, and α-trypsin, composed of two cleaved chains bound by a disulfide bridge [Santos AMC et al, 2008]. Trypsin is required for the partial hydrolysis of chymotrypsinogen to chymotrypsin, and most pancreatic digestive enzyme precursors are activated by trypsin in the same manner as chymotrypsin in the intestinal lumen.

As part of the defense against trypsin-induced self injury in the pancreas, internal TIs such as the serine protease inhibitor Kazal type 1 (SPINK1 or human pancreatic trypsin inhibitor) and bovine pancreatic TI in the pancreatic juice and α1-antitrypsin in the serum bind tightly to active trypsin [Voet D and Voet JG, 1995].

Secretion of pancreatic digestive enzymes including trypsin is regulated mainly by CCK released from enteroendocrine I cells in the duodenal mucosa of the small intestine [Wang BJ and Cui ZJ, 2007], and CCK release is controlled by multiple mechanisms [Caron J et al, 2017]. One such mechanism is trypsin-mediated negative feedback regulation, in which increased trypsin secretion leads to decreased levels of trypsin-sensitive luminal CCK-releasing factors (LCRFs) in several mammalian species and MP in rodents [Liddle RA, 1995; Miyasaka K and Funakoshi A, 1998].

Therefore, ingestion of RSF containing trypsin inhibitory action or protease inhibitors such as camostat inhibits trypsin activity in the intestinal lumen, which leads to increased luminal levels of the abovementioned trypsin-sensitive peptides and thereby stimulation of CCK release [Green GM and Miyasaka K, 1983; Cuber JC et al, 1990; Miyasaka K et al, 1989; Cuber JC et al, 1990; Komarnytsky S et al, 2011].

How It Is Measured or Detected

A description of the type(s) of measurements that can be employed to evaluate the KE and the relative level of scientific confidence in those measurements.These can range from citation of specific validated test guidelines, citation of specific methods published in the peer reviewed literature, or outlines of a general protocol or approach (e.g., a protein may be measured by ELISA). Do not provide detailed protocols. More help

Activity of trypsin inhibitors is measured colorimetrically using mixture of multiple dilutions of samples (TIs), trypsin and its substrate. Standard procedures for measuring TI activities in soy bean products are released as AACCI Method 22-40.01 [AACCI, 2009] and AOCS Method Ba 12-75 [AOCC, 2017]. ISO standard for measuring TI activities is also established as Standard 14902:2001 [ISO, 2012]. The two methods of modified AACC 20-40.01 and ISO 14902 were compared to show that the values obtained by these two methods are not directly comparable [Sueiro S et al, 2015]. Modified standard method is proposed reconsidering the levels of dilutions and volumes, reaction sequence and other factors [Liu K, 2019].

Domain of Applicability

A description of the scientific basis for the indicated domains of applicability and the WoE calls (if provided). More help

Trypsin is a digestive enzyme expressed in many vertebrates, and its molecular weight and isoforms vary among animal species, for example, human cationic and anionic trypsins (trypsins 1 and 2) and mesotrypsin, bovine cationic and anionic trypsins, and rat anionic trypsin and P23 [Chen JM and Claude Férec C, 2013; Fukuoka S and Nyaruhucha CM, 2002]. However, their three-dimensional structures are highly conserved among species [Baird Jr TT, 2013].

The natural substrate for trypsin is generally any peptide that contains Lys or Arg. The active site of trypsin has a specific catalytic triad structure composed of serine, histidine, and aspartate, and the flanking amino acid sequences are entirely conserved [Baird Jr TT and Craik CS, 2013; Baird Jr TT, 2017].

Therefore, TIs show comparable enzymatic inhibition of trypsin molecules among animal species including humans and rats [Savage GP and Morrison SC, 2003].

References

List of the literature that was cited for this KE description. More help

1. AACCI (2009) American Association of Cereal Chemists. Approved methods of analysis, 11th Ed. Method 22-40.01. Measurement of trypsin inhibitor activity of soy products—spectrophotometric method. First approval Nov 7, 1973; Reapproved Nov 3, 1999. AACC International, St. Paul. doi: 10.1094/AACCIntMethod-22-40.01

2. AOCS (2017) American Oil Chemists’ Society. Official and tentative methods of the American Oil Society, 3rd Ed. Method Ba 12-75. Trypsin inhibitor activity. First approval 1980; Reapproved 2009. American Oil Chemist Society, Champaign

3. Baird Jr TT, Craik CS: Trypsin. Academic Press, Cambridge, Massachusetts (pp)2594-2600,2013

4. Baird Jr TT: Trypsin. Elsevier,2017

5. Caron J, Domenger D, Dhulster P, Ravallec R, Cudennec B: Protein digestion-derived peptides and the peripheral regulation of food intake. Front Endocrinol (Lausanne) 8:85,2017

6. Chen J-M, Claude Férec C: Human trypsins. Academic Press, Cambridge, Massachusetts (pp) 2600-2609,2013

7. Cuber JC, Bernard G, Fushiki T, Bernard C, Yamanishi R, Sugimoto E, Chayvialle JA: Luminal CCK-releasing factors in the isolated vascularly perfused rat duodenojejunum. Am J Physiol 259:G191-197,1990

8. Fukuoka S, Nyaruhucha CM: Expression and functional analysis of rat P23, a gut hormone-inducible isoform of trypsin, reveals its resistance to proteinaceous trypsin inhibitors. Biochim Biophys Acta 1588:106-112,2002

9. Green GM, Miyasaka K: Rat pancreatic response to intestinal infusion of intact and hydrolyzed protein. Am J Physiol 245:G394-8,1983

10. ISO (2012) International Organization for Standardization. Standard 14902:2001. Animal feeding stuffs—determination of trypsin inhibitor activity of soya products. Approved Oct 2001; Reapproved Aug 2012. International Organization for Standardization, Geneva

11. Komarnytsky S, Cook A, Raskin I: Potato protease inhibitors inhibit food intake and increase circulating cholecystokinin levels by a trypsin-dependent mechanism. Int J Obes (Lond) 35:236-243,2011

12. Liddle RA: Regulation of cholecystokinin secretion by intraluminal releasing factors. Am J Physiol 269:G319-27,1995

13. Liu K: Soybean trypsin inhibitor assay: further improvement of the standard method approved and reapproved by American Oil Chemists’ Society and American Association of Cereal Chemists International. J Am Oil Chem Soc 96: 635–645,2019

14. Miyasaka K, Nakamura R, Funakoshi A, Kitani K: Stimulatory effect of monitor peptide and human pancreatic secretory trypsin inhibitor on pancreatic secretion and cholecystokinin release in conscious rats. Pancreas 4:139-144,1989

15. Miyasaka K, Funakoshi A: Luminal feedback regulation, monitor peptide, CCK-releasing peptide, and CCK receptors. Pancreas 16:277-283,1998

16. Santos AMC, de Oliveira JS, Bittar ER, da Silva AL, dos Mares Guia ML, Bemquerer MP, Santoro MM: Improved purification process of β- and α-trypsin isoforms by ion-exchange chromatography. Braz Arch Biol Technol 51: 711-721,2008

17. Savage GP, Morrison SC: Trypsin inhibitors. Elsevier (pp) 5878-5884,2003

18. Sueiro S, Hermida M, González M, Lois A, Rodríguez?Otero JL: A comparison of the ISO and AACC methods for determining the activity of trypsin Inhibitors in soybean meal. J Am Oil Chem Soc 92:1391–1397,2015

19. Voet D, Voet JG: Biochemistry (2nd ed.). John Wiley & Sons (pp) 396-400,1995

20. Wang BJ, Cui ZJ: How does cholecystokinin stimulate exocrine pancreatic secretion? From birds, rodents, to humans.. Am J Physiol Regul Integr Comp Physiol 292:R666-78,2007