chymotrypsin

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chymotrypsin
Crystallographic structure of Bos taurus chymotrypsinogen.
Identifiers
EC number	3.4.21.1
CAS number	9004-07-3
Databases
IntEnz	IntEnz view
BRENDA	BRENDA entry
ExPASy	NiceZyme view
KEGG	KEGG entry
MetaCyc	metabolic pathway
PRIAM	profile
PDB structures	RCSB PDB PDBe PDBsum
Gene Ontology	AmiGO / EGO
Search PMC articles PubMed articles NCBI proteins

chymotrypsin C
Identifiers
EC number	3.4.21.2
CAS number	9036-09-3
Databases
IntEnz	IntEnz view
BRENDA	BRENDA entry
ExPASy	NiceZyme view
KEGG	KEGG entry
MetaCyc	metabolic pathway
PRIAM	profile
PDB structures	RCSB PDB PDBe PDBsum
Search PMC articles PubMed articles NCBI proteins

Chymotrypsin (EC 3.4.21.1, chymotrypsins A and B, alpha-chymar ophth, avazyme, chymar, chymotest, enzeon, quimar, quimotrase, alpha-chymar, alpha-chymotrypsin A, alpha-chymotrypsin) is a digestive enzyme component of pancreatic juice acting in the duodenum where it performs proteolysis, the breakdown of proteins and polypeptides. Chymotrypsin preferentially cleaves peptide amide bonds where the carboxyl side of the amide bond (the P₁ position) is a large hydrophobic amino acid (tyrosine, tryptophan, and phenylalanine). These amino acids contain an aromatic ring in their sidechain that fits into a 'hydrophobic pocket' (the S₁ position) of the enzyme. It is activated in the presence of trypsin. The hydrophobic and shape complementarity between the peptide substrate P₁ sidechain and the enzyme S₁ binding cavity accounts for the substrate specificity of this enzyme. Chymotrypsin also hydrolyzes other amide bonds in peptides at slower rates, particularly those containing leucine and methionine at the P₁ position.

Structurally, it is the archetypal structure for its superfamily, the PA clan of proteases.

Activation

Chymotrypsin is synthesized in the pancreas by protein biosynthesis as a precursor called chymotrypsinogen that is enzymatically inactive. On cleavage by trypsin into two parts that are still connected via an S-S bond, cleaved chymotrypsinogen molecules can activate each other by removing two small peptides in a trans-proteolysis. The resulting molecule is active chymotrypsin, a three-polypeptide molecule interconnected via disulfide bonds.

Mechanism of action and kinetics

See also: catalytic triad

In vivo, chymotrypsin is a proteolytic enzyme (Serine protease) acting in the digestive systems of many organisms. It facilitates the cleavage of peptide bonds by a hydrolysis reaction, which despite being thermodynamically favorable occurs extremely slowly in the absence of a catalyst. The main substrates of chymotrypsin include tryptophan, tyrosine, phenylalanine, leucine, and methionine, which are cleaved at the carboxyl terminal. Like many proteases, chymotrypsin will also hydrolyse amide bonds in vitro, a virtue that enabled the use of substrate analogs such as N-acetyl-L-phenylalanine p-nitrophenyl amide for enzyme assays.

Mechanism of peptide bond cleavage in α-chymotrypsin

Chymotrypsin cleaves peptide bonds by attacking the unreactive carbonyl group with a powerful nucleophile, the serine 195 residue located in the active site of the enzyme, which briefly becomes covalently bonded to the substrate, forming an enzyme-substrate intermediate. Along with histidine 57 and aspartic acid 102, this serine residue constitutes the catalytic triad of the active site.

These findings rely on inhibition assays and the study of the kinetics of cleavage of the aforementioned substrate, exploiting the fact that the enzyme-substrate intermediate p-nitrophenolate has a yellow colour, enabling us to measure its concentration by measuring light absorbance at 410 nm.

It was found that the reaction of chymotrypsin with its substrate takes place in two stages, an initial “burst” phase at the beginning of the reaction and a steady-state phase following Michaelis-Menten kinetics. It is also called "ping-pong" mechanism. The mode of action of chymotrypsin explains this as hydrolysis takes place in two steps. First acylation of the substrate to form an acyl-enzyme intermediate and then deacylation in order to return the enzyme to its original state. This occurs via the concerted action of the three amino acid residues in the catalytic triad. Aspartate hydrogen bonds to the N-δ hydrogen of histidine, increasing the pKa of its ε nitrogen and thus making it able to deprotonate serine. It is this deprotonation that allows the serine side chain to act as a nucleophile and bind to the electron-deficient carbonyl carbon of the protein main chain. Ionization of the carbonyl oxygen is stabilized by formation of two hydrogen bonds to adjacent main chain N-hydrogens. This occurs in the oxyanion hole. This forms a tetrahedral adduct and breakage of the peptide bond. An acyl-enzyme intermediate, bound to the serine, is formed, and the newly formed amino terminus of the cleaved protein can dissociate. In the second reaction step, a water molecule is activated by the basic histidine, and acts as a nucleophile. The oxygen of water attacks the carbonyl carbon of the serine-bound acyl group, resulting in formation of a second tetrahedral adduct, regeneration of the serine -OH group, and release of a proton, as well as the protein fragment with the newly formed carboxyl terminus

Isozymes

chymotrypsinogen B1 Identifiers Symbol CTRB1 Entrez 1504 HUGO 2521 OMIM 118890 RefSeq NM_001906 UniProt P17538 Other data Locus Chr. 16 q23.1

chymotrypsinogen B2 Identifiers Symbol CTRB2 Entrez 440387 HUGO 2522 RefSeq NM_001025200 UniProt Q6GPI1 Other data Locus Chr. 16 q22.3

chymotrypsin C (caldecrin) Identifiers Symbol CTRC Entrez 11330 HUGO 2523 OMIM 601405 RefSeq NM_007272 UniProt Q99895 Other data Locus Chr. 1 p36.21

See also

Trypsin PA clan of proteases

References

Further reading

• Stryer L, Berg JM, Tymoczko JL (2002). Biochemistry. San Francisco: W.H. Freeman. ISBN 0-7167-4684-0. 
• Grisham CM, Reginald H (2005). Biochemistry. Australia: Thomson Brooks/Cole. ISBN 0-534-49033-6. 

External links

• The MEROPS online database for peptidases and their inhibitors: S01.001
• Chymotrypsin at the US National Library of Medicine Medical Subject Headings (MeSH)

UpToDate Contents

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• 1. 膵外分泌機能検査 pancreatic exocrine function tests
• 2. 小児における慢性膵炎の臨床症状および診断 clinical manifestations and diagnosis of chronic pancreatitis in children
• 3. 鉤虫感染 hookworm infection
• 4. 遺伝性膵炎 hereditary pancreatitis
• 5. 肥満細胞由来のメディエーター mast cell derived mediators

English Journal

• Asteropsins B-D, sponge-derived knottins with potential utility as a novel scaffold for oral peptide drugs.

• Li H1, Bowling JJ2, Su M3, Hong J4, Lee BJ5, Hamann MT6, Jung JH7.Author information 1College of Pharmacy, Pusan National University, Busan 609-735, Republic of Korea. Electronic address: lihuayue@naver.com.2Department of Pharmacognosy, School of Pharmacy, The University of Mississippi, Oxford, MN 38677, USA. Electronic address: bowlingjj@gmail.com.3College of Pharmacy, Pusan National University, Busan 609-735, Republic of Korea. Electronic address: smz0310@163.com.4College of Pharmacy, Kyung Hee University, Seoul 130-701, Republic of Korea. Electronic address: jhong@khu.ac.kr.5College of Pharmacy, Seoul National University, Seoul 151-742, Republic of Korea. Electronic address: lbj@nmr.snu.ac.kr.6Department of Pharmacognosy, School of Pharmacy, The University of Mississippi, Oxford, MN 38677, USA. Electronic address: mthamann@olemiss.edu.7College of Pharmacy, Pusan National University, Busan 609-735, Republic of Korea. Electronic address: jhjung@pusan.ac.kr.AbstractBACKGROUND: Known linear knottins are unsuitable as scaffolds for oral peptide drug due to their gastrointestinal instability. Herein, a new subclass of knottin peptides from Porifera is structurally described and characterized regarding their potential for oral peptide drug development.
• Biochimica et biophysica acta.Biochim Biophys Acta.2014 Mar;1840(3):977-84. doi: 10.1016/j.bbagen.2013.11.001. Epub 2013 Nov 10.
• BACKGROUND: Known linear knottins are unsuitable as scaffolds for oral peptide drug due to their gastrointestinal instability. Herein, a new subclass of knottin peptides from Porifera is structurally described and characterized regarding their potential for oral peptide drug development.METHODS: Ast
• PMID 24225326

• Effect of limited enzymatic hydrolysis on linoleic acid binding properties of β-lactoglobulin.

• Sponton OE, Perez AA, Carrara C, Santiago LG.Author information Grupo de Biocoloides, Instituto de Tecnología de Alimentos, Universidad Nacional del Litoral, 1 de Mayo 3250 (3000), Santa Fe, Argentina.Abstractβ-Lactoglobulin (BLG) is a member of lipocalin family, proteins with ability to bind small hydrophobic ligands, such as retinol, vitamins and fatty acids. Moreover, BLG is susceptible to protease action producing a wide range of polypeptides depending on the hydrolysis degree (HD). In the present work, the effect of limited enzymatic hydrolysis on fatty acid binding properties of BLG was studied. Linoleic acid (LA) was used as a model fatty acid. Limited enzymatic hydrolysis was performed using α-chymotrypsin immobilised on agarose microparticles. BLG hydrolysates were produced at HD: 1%, 3% and 5%. In order to determine the influence of HD on BLG molecular weight SDS-PAGE was used. BLG structural modification and LA binding properties were monitored by means of fluorescence spectroscopic techniques. The increase in HD produced: (i) a BLG degradation and a molecular weight distribution of BLG hydrolysates and (ii) an increased exposition of buried hydrophobic residues, however it was observed a decrease in surface hydrophobicity possibly due to a deterioration of hydrophobic protein domains. It was observed that enzymatic hydrolysis treatment produced a decrease in BLG ability for binding LA. It was concluded that limited enzymatic hydrolysis could deteriorate the specific site on BLG structure necessary for binding LA.
• Food chemistry.Food Chem.2014 Mar 1;146:577-82. doi: 10.1016/j.foodchem.2013.09.089. Epub 2013 Sep 25.
• β-Lactoglobulin (BLG) is a member of lipocalin family, proteins with ability to bind small hydrophobic ligands, such as retinol, vitamins and fatty acids. Moreover, BLG is susceptible to protease action producing a wide range of polypeptides depending on the hydrolysis degree (HD). In the present w
• PMID 24176383

• Antioxidant properties of Australian canola meal protein hydrolysates.

• Alashi AM, Blanchard CL, Mailer RJ, Agboola SO, Mawson AJ, He R, Girgih A, Aluko RE.Author information E. H. Graham Centre for Agricultural Innovation, Charles Sturt University, Locked Bag 588, Wagga, NSW 2678, Australia; School of Agricultural and Wine Sciences, Charles Sturt University, Locked Bag 588, Wagga, NSW 2678, Australia; Department of Human Nutritional Sciences, The Richardson Center for Functional Foods and Nutraceuticals, University of Manitoba, Winnipeg R3T 2N2, Canada. Electronic address: aalashi@csu.edu.au.AbstractAntioxidant activities of canola protein hydrolysates (CPHs) and peptide fractions prepared using five proteases and ultrafiltration membranes (1, 3, 5, and 10kDa) were investigated. CPHs had similar and adequate quantities of essential amino acids. The effective concentration that scavenged 50% (EC50) of the ABTS(+) was greatest for the <1kDa pancreatin fraction at 10.1μg/ml. CPHs and peptide fractions scavenged DPPH(+) with most of the EC50 values being <1.0mg/ml. Scavenging of superoxide radical was generally weak, except for the <1kDa pepsin peptide fraction that had a value of 51%. All CPHs inhibited linoleic acid oxidation with greater efficiency observed for pepsin hydrolysates. The oxygen radical absorbance capacity of Alcalase, chymotrypsin and pepsin hydrolysates was found to be better than that of glutathione (GSH) (p<0.05). These results show that CPHs have the potential to be used as bioactive ingredients in the formulation of functional foods against oxidative stress.
• Food chemistry.Food Chem.2014 Mar 1;146:500-6. doi: 10.1016/j.foodchem.2013.09.081. Epub 2013 Sep 25.
• Antioxidant activities of canola protein hydrolysates (CPHs) and peptide fractions prepared using five proteases and ultrafiltration membranes (1, 3, 5, and 10kDa) were investigated. CPHs had similar and adequate quantities of essential amino acids. The effective concentration that scavenged 50% (EC
• PMID 24176374

Japanese Journal

• Identification of a New IgE-Binding Epitope of Peanut Oleosin That Cross-Reacts with Buckwheat

• KOBAYASHI Shoko,KATSUYAMA Shinta,WAGATSUMA Tamae [他],OKADA Shinji,TANABE Soichi
• Bioscience, biotechnology, and biochemistry 76(6), 1182-1188, 2012-06-23
• … A cross-reactive peptide was isolated from the α-chymotrypsin hydrolysate of peanut. …
• NAID 10030818299

• An extracellular serine protease produced by Vibrio vulnificus NCIMB 2137, a metalloprotease-gene negative strain isolated from a diseased eel

• Miyoshi Shin-ichi,Jiyou Wang,Katoh Keizo,Senoh Mitsutoshi,Mizuno Tamaki,Maehara Yoko
• World Journal of Microbiology & Biotechnology 28(4), 1633-1639, 2012-04-00
• … We also purified VvsA from the culture supernatant through ammonium sulfate fractionation, gel filtration and ion-exchange column chromatography, and the enzyme was demonstrated to be a chymotrypsin-like protease, as well as those from some vibrios. …
• NAID 120005301994

• トリレオウイルスの蛋白質分解酵素処理による感染価上昇

• 高瀬 公三,直原 良子,岩瀬 夏代 [他],山崎 憲一,小尾 岳士,タカセ コウゾウ,ジキハラ リョウコ,イワセ ナツヨ,ヤマザキ ケンイチ,オビ タケシ,TAKASE Kozo,JIKIHARA Ryoko,IWASE Natsuyo,YAMAZAKI Kenichi,OBI Takesi,髙瀬 公三
• 鹿児島大学農学部学術報告 (62), 59-64, 2012-03-00
• … Trypsin, chymotrypsin and dispase were effective in increasing the infectivity titer of ARV more than ten times when titrated into cultured chicken kidney cells. …
• NAID 40019245009

Related Links

• CHYMOTRYPSIN: Uses, Side Effects, Interactions and ...

Find patient medical information for CHYMOTRYPSIN on WebMD including its uses, effectiveness, side effects and safety, interactions, user ratings and products that have it. ... Chymotrypsin is safe when used in the eye by a healthcare ...

• Chymotrypsin - Worthington Enzyme Manual - Enzymes ...

I.U.B.: 3.4.21.1 C.A.S.: 9004-07-3 Enzymatic Reaction (image will open in a new window) Chymotrypsin is a serine endopeptidase produced by the acinar cells of the pancreas. Chymotrypsin becomes activated after proteolysis of ...

Related Pictures

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★リンクテーブル★

リンク元	「キモトリプシン」「chymotryptic」
拡張検索	「alpha 1-antichymotrypsin」「α-antichymotrypsin deficiency」「α-antichymotrypsin欠損症」「chymotrypsinogen」

「キモトリプシン」

　　[★]

chyme 糜粥 →　これに対するトリプシンという意味で命名されたのだろうか。

英

chymotrypsin

• セリンプロテアーゼの一種。
• ヒトでは膵臓からキモトリプシノーゲンが分泌され、トリプシンやキモトリプシンにより分解され活性のあるキモトリプシンとなる。
• 六員環を持つアミノ酸を分解する、らしい
• Tyr, Phe, TrpのC末端側のペプチド結合を特異的に加水分解するセリンエンドペプチダーゼ．Leu,Met, Ala, Asp, Gluは低い率で切断される．感受性の高いアミノ酸のアミドとエステルにも作用し，ペプチド合成に使用される(http://www.bio-concierge.com/detail.php?id=5763)

「chymotryptic」

　　[★]

• adj.

• キモトリプシンの

関

chymotrypsin

「alpha 1-antichymotrypsin」

　　[★]

α1アンチキモトリプシン、α1-アンチキモトリプシン

「α-antichymotrypsin deficiency」

　　[★] αアンチキモトリプシン欠損症

「α-antichymotrypsin欠損症」

　　[★] αアンチキモトリプシン欠損症

「chymotrypsinogen」

　　[★]

キモトリプシノーゲン