Annotations: 4Y0Y

Domain Annotation: SCOP2 Classification SCOP2 Database Homepage

Chains	Type	Family Name	Domain Identifier	Family Identifier	Provenance Source (Version)
A [auth E]	SCOP2B Superfamily	Trypsin-like serine proteases	8037496	3000114	SCOP2B (2022-06-29)
B [auth I]	SCOP2B Superfamily	BPTI-like	8038485	3000628	SCOP2B (2022-06-29)

Domain Annotation: ECOD Classification ECOD Database Homepage

Chains	Family Name	Domain Identifier	Architecture	Possible Homology	Homology	Topology	Family	Provenance Source (Version)
A [auth E]	Trypsin_1	e4y0yE1	A: beta barrels	X: cradle loop barrel	H: RIFT-related	T: FMN-binding split barrel 2	F: Trypsin_1	ECOD (1.6)
B [auth I]	Kunitz_BPTI	e4y0yI1	A: few secondary structure elements	X: BPTI-like (From Topology)	H: BPTI-like (From Topology)	T: BPTI-like	F: Kunitz_BPTI	ECOD (1.6)

Domain Annotation: CATH CATH Database Homepage

Chain	Domain	Class	Architecture	Topology	Homology	Provenance Source (Version)
A [auth E]	2.40.10.10	Mainly Beta	Beta Barrel	Thrombin, subunit H	Trypsin-like serine proteases	CATH (4.3.0)
B [auth I]	4.10.410.10	Few Secondary Structures	Irregular	Factor Xa Inhibitor	Pancreatic trypsin inhibitor Kunitz domain	CATH (4.3.0)

Protein Family Annotation Pfam Database Homepage

Chains	Accession	Name	Description	Comments	Source
A [auth E]	PF00089	Trypsin (Trypsin)	Trypsin	-	Domain
B [auth I]	PF00014	Kunitz/Bovine pancreatic trypsin inhibitor domain (Kunitz_BPTI)	Kunitz/Bovine pancreatic trypsin inhibitor domain	Indicative of a protease inhibitor, usually a serine protease inhibitor. Structure is a disulfide rich alpha+beta fold. BPTI (bovine pancreatic trypsin inhibitor) is an extensively studied model structure. Certain family members are similar to the ...	Indicative of a protease inhibitor, usually a serine protease inhibitor. Structure is a disulfide rich alpha+beta fold. BPTI (bovine pancreatic trypsin inhibitor) is an extensively studied model structure. Certain family members are similar to the tick anticoagulant peptide (TAP, Swiss:P17726). This is a highly selective inhibitor of factor Xa in the blood coagulation pathways [1]. TAP molecules are highly dipolar [2], and are arranged to form a twisted two- stranded antiparallel beta-sheet followed by an alpha helix [1].	Domain

Gene Ontology: Gene Product Annotation Gene Ontology Database Homepage

Chains	Polymer	Molecular Function	Biological Process	Cellular Component
A [auth E]	Cationic trypsin	peptidase activity catalytic activity, acting on a protein hydrolase activity catalytic activity endopeptidase activity serine hydrolase activity serine-type peptidase activity serine-type endopeptidase activity protein binding binding serpin family protein binding cation binding ion binding metal ion binding peptidase activity catalytic activity, acting on a protein hydrolase activity catalytic activity endopeptidase activity serine hydrolase activity serine-type peptidase activity serine-type endopeptidase activity protein binding binding serpin family protein binding cation binding ion binding metal ion binding small molecule binding	proteolysis metabolic process cellular process primary metabolic process protein metabolic process macromolecule metabolic process multicellular organismal process digestion	protein-containing complex serine protease inhibitor complex protease inhibitor complex peptidase inhibitor complex cellular anatomical structure extracellular region extracellular space
B [auth I]	Pancreatic trypsin inhibitor	cation binding ion binding binding calcium ion binding metal ion binding small molecule binding enzyme regulator activity molecular function inhibitor activity peptidase regulator activity serine-type endopeptidase inhibitor activity molecular function regulator activity enzyme inhibitor activity peptidase inhibitor activity endopeptidase regulator activity cation binding ion binding binding calcium ion binding metal ion binding small molecule binding enzyme regulator activity molecular function inhibitor activity peptidase regulator activity serine-type endopeptidase inhibitor activity molecular function regulator activity enzyme inhibitor activity peptidase inhibitor activity endopeptidase regulator activity endopeptidase inhibitor activity protein binding enzyme binding zymogen binding protease binding sulfate binding anion binding sulfur compound binding potassium channel regulator activity channel regulator activity transporter inhibitor activity ion channel inhibitor activity ion channel regulator activity potassium channel inhibitor activity transporter regulator activity channel inhibitor activity	negative regulation of hydrolase activity regulation of cellular process negative regulation of proteolysis regulation of serine-type endopeptidase activity regulation of catalytic activity negative regulation of biological process negative regulation of catalytic activity negative regulation of endopeptidase activity regulation of primary metabolic process negative regulation of peptidase activity regulation of proteolysis regulation of serine-type peptidase activity proteolysis regulation of endopeptidase activity negative regulation of cellular process negative regulation of hydrolase activity regulation of cellular process negative regulation of proteolysis regulation of serine-type endopeptidase activity regulation of catalytic activity negative regulation of biological process negative regulation of catalytic activity negative regulation of endopeptidase activity regulation of primary metabolic process negative regulation of peptidase activity regulation of proteolysis regulation of serine-type peptidase activity proteolysis regulation of endopeptidase activity negative regulation of cellular process protein metabolic process negative regulation of protein metabolic process negative regulation of macromolecule metabolic process negative regulation of serine-type endopeptidase activity regulation of biological process negative regulation of serine-type peptidase activity regulation of protein metabolic process negative regulation of metabolic process regulation of peptidase activity biological regulation negative regulation of molecular function primary metabolic process regulation of macromolecule metabolic process regulation of molecular function regulation of hydrolase activity metabolic process cellular process macromolecule metabolic process regulation of metabolic process multicellular organismal process regulation of body fluid levels response to stimulus regulation of cell activation negative regulation of cell adhesion negative regulation of platelet activation regulation of coagulation regulation of biological quality response to wounding negative regulation of homotypic cell-cell adhesion negative regulation of wound healing negative regulation of blood coagulation response to external stimulus blood coagulation negative regulation of hemostasis regulation of platelet activation regulation of response to stimulus negative regulation of response to external stimulus negative regulation of cell-cell adhesion regulation of wound healing negative regulation of multicellular organismal process platelet activation regulation of response to external stimulus homotypic cell-cell adhesion regulation of response to wounding cell adhesion cell-cell adhesion response to stress regulation of response to stress coagulation regulation of cell-cell adhesion regulation of multicellular organismal process regulation of hemostasis wound healing negative regulation of response to stimulus regulation of homotypic cell-cell adhesion regulation of cell adhesion regulation of blood coagulation hemostasis cell activation negative regulation of platelet aggregation negative regulation of response to wounding platelet aggregation negative regulation of cell activation regulation of platelet aggregation negative regulation of coagulation cellular response to stimulus negative regulation of thrombin-activated receptor signaling pathway signaling negative regulation of signaling regulation of signal transduction negative regulation of G protein-coupled receptor signaling pathway negative regulation of cell communication cell communication thrombin-activated receptor signaling pathway signal transduction regulation of G protein-coupled receptor signaling pathway regulation of signaling regulation of thrombin-activated receptor signaling pathway negative regulation of signal transduction regulation of cell communication G protein-coupled receptor signaling pathway zymogen activation gene expression macromolecule biosynthetic process protein maturation biosynthetic process protein processing trypsinogen activation	protein-containing complex serine protease inhibitor complex protease inhibitor complex peptidase inhibitor complex cellular anatomical structure extracellular region extracellular space

InterPro: Protein Family Classification InterPro Database Homepage

Chains	Accession	Name	Type
A [auth E]	IPR009003	Peptidase S1, PA clan	Homologous Superfamily
A [auth E]	IPR001314	Peptidase S1A, chymotrypsin family	Family
A [auth E]	IPR033116	Serine proteases, trypsin family, serine active site	Active Site
A [auth E]	IPR001254	Serine proteases, trypsin domain	Domain
A [auth E]	IPR043504	Peptidase S1, PA clan, chymotrypsin-like fold	Homologous Superfamily
A [auth E]	IPR050127	Serine Proteases (Peptidase S1 Family)	Family
A [auth E]	IPR018114	Serine proteases, trypsin family, histidine active site	Active Site
B [auth I]	IPR020901	Proteinase inhibitor I2, Kunitz, conserved site	Conserved Site
B [auth I]	IPR036880	Pancreatic trypsin inhibitor Kunitz domain superfamily	Homologous Superfamily
B [auth I]	IPR002223	Pancreatic trypsin inhibitor Kunitz domain	Domain
B [auth I]	IPR050098	Tissue factor pathway inhibitor/Kunitz-type serine protease inhibitor-like	Family

RCSB PDB Core Operations are funded by the U.S. National Science Foundation (DBI-2321666), the US Department of Energy (DE-SC0019749), and the National Cancer Institute, National Institute of Allergy and Infectious Diseases, and National Institute of General Medical Sciences of the National Institutes of Health under grant R01GM157729.