Related Experiment Video

Updated: Aug 8, 2026

The Determination of Protease Specificity in Mouse Tissue Extracts by MALDI-TOF Mass Spectrometry: Manipulating PH to Cause Specificity Changes
09:47

The Determination of Protease Specificity in Mouse Tissue Extracts by MALDI-TOF Mass Spectrometry: Manipulating PH to Cause Specificity Changes

Published on: May 25, 2018

Human mesotrypsin exhibits restricted S1' subsite specificity with a strong preference for small polar side chains

Edit Szepessy1, Miklós Sahin-Tóth

  • 1Department of Molecular and Cell Biology, Boston University, Goldman School of Dental Medicine, MA, USA.

The FEBS Journal
|June 9, 2006
PubMed

Insights

Mesotrypsin, resistant to inhibitors, selectively cleaves specific peptide bonds in alpha1-antitrypsin. This reveals mesotrypsin

Area of Science:

  • Biochemistry
  • Protease Function
  • Enzyme Specificity

Background:

  • Mesotrypsin is a human trypsin isoform resistant to inhibitors.
  • Previous studies suggested mesotrypsin is a defective digestive protease due to limited zymogen activation.
  • The interaction of mesotrypsin with serpin-type inhibitors like alpha1-antitrypsin (alpha1AT) was not well understood.

Purpose of the Study:

  • To investigate the substrate specificity of mesotrypsin.
  • To determine if mesotrypsin's inhibitor resistance impacts its enzymatic activity on specific peptide bonds.
  • To explore the potential of alpha1-antitrypsin Pittsburgh as a mesotrypsin inhibitor.

Main Methods:

  • Enzyme kinetics assays using wild-type and mutant alpha1-antitrypsin.
  • Analysis of peptide bond cleavage specificity by mesotrypsin.
  • Determination of inhibition rates for alpha1AT Pittsburgh against mesotrypsin.

Main Results:

  • Mesotrypsin selectively cleaved the Lys10-Thr11 bond in alpha1AT.
  • Mesotrypsin exhibited high specificity for lysyl peptide bonds with Ser or Thr at the P1' position.
  • Alpha1AT Pittsburgh effectively inhibited mesotrypsin via the serpin mechanism.

Conclusions:

  • Mesotrypsin is not a defective protease but possesses a specific substrate preference for Lys/Arg-Ser/Thr bonds.
  • This specificity explains its inability to activate pancreatic zymogens.
  • Alpha1-antitrypsin Pittsburgh can inhibit mesotrypsin, offering a strategy against its inhibitor resistance.

More Related Videos

X-Ray Crystallography to Study the Oligomeric State Transition of the Thermotoga maritima M42 Aminopeptidase TmPep105011:27

X-Ray Crystallography to Study the Oligomeric State Transition of the Thermotoga maritima M42 Aminopeptidase TmPep1050

Published on: May 13, 2020

Computational Prediction of Amino Acid Preferences of Potentially Multispecific Peptide-Binding Domains Involved in Protein-Protein Interactions06:50

Computational Prediction of Amino Acid Preferences of Potentially Multispecific Peptide-Binding Domains Involved in Protein-Protein Interactions

Published on: January 26, 2024

Related Concept Videos

Ligand Binding Sites02:40

Ligand Binding Sites

Proteins are dynamic macromolecules that carry out a wide variety of essential processes; however, the activities of most proteins depend on their interactions with other molecules or ions, known as ligands.
Protein-ligand interactions are quite specific; even though numerous potential ligands surround a cellular protein at any given time, only a particular ligand can bind to that protein. Moreover, a ligand binds only to a dedicated area on the surface of the protein, known as the...
Conserved Binding Sites01:49

Conserved Binding Sites

Many proteins’ biological role depends on their interactions with their ligands, small molecules that bind to specific locations on the protein known as ligand-binding sites. Ligand-binding sites are often conserved among homologous proteins as these sites are critical for protein function.
Binding sites are often located in large pockets, and if their location on a protein’s surface is unknown, it can be predicted using various approaches. The energetic method computationally analyses the...
Ligand Binding and Linkage00:49

Ligand Binding and Linkage

Allosteric proteins have more than one ligand binding site; the binding of a ligand to any of these sites influences the binding of ligands to the other sites. When a protein is allosteric, its binding sites are called coupled or linked.  In the case of enzymes, the site that binds to the substrate is known as the active site and the other site is known as the regulatory site. When a ligand binds to the regulatory site, this leads to conformational changes in the protein that can influence the...
Allosteric Proteins-ATCase01:19

Allosteric Proteins-ATCase

Binding sites linkages can regulate a protein's function.  For example, enzyme activity is often regulated through a feedback mechanism where the end product of the biochemical process serves as an inhibitor.
Aspartate transcarbamoylase (ATCase) is a cytosolic enzyme that catalyzes the condensation of L-aspartate and carbamoyl phosphate to  N-carbamoyl-L-aspartate. This reaction is the first step in pyrimidine biosynthesis. UTP and CTP, the end products of the pyrimidine synthesis pathway,...
Mitochondrial Precursor Proteins01:39

Mitochondrial Precursor Proteins

Mitochondrial precursors are partially unfolded or loosely folded polypeptide chains. Newly synthesized precursors are inhibited from spontaneously folding into their native conformation by the cytosolic chaperones, heat shock proteins 70 (Hsp70), and mitochondrial import stimulation factors (MSFs). Precursors bound to MSFs are guided to the TOM70-TOM37 receptors, while precursors bound to Hsp70  chaperones are targetted to TOM20-TOM22 receptor complexes.
Most of the mitochondrial precursors...