Commonly Used Proteases in Research: Fundamentals and Representative Applications
Commonly Used Proteases in Research: Fundamentals and Representative Applications
Proteases are enzymes that catalyze the hydrolysis of peptide bonds in proteins or polypeptides. In life-science research, they are widely used for proteomics digestion, limited proteolysis for domain mapping, deproteinization of nucleic-acid samples, antibody fragmentation, and recombinant-protein processing. In industry, proteases are applied in processes such as leather dehairing and softening, silk degumming, detergent stain removal, food-protein modification, and baking dough conditioning. In research settings, the key to protease use is not maximizing hydrolysis, but rather obtaining cleavage products that are reproducible, interpretable, and compatible with downstream analyses by defining a clear reaction window and a robust quenching strategy. This review outlines classification frameworks, critical experimental variables, and the mechanisms and practical considerations of commonly used research proteases, and links these principles to representative enzyme-reagent listings to support selection and workflow standardization.
Keywords: proteases; peptide-bond hydrolysis; substrate specificity; proteomics; limited proteolysis; antibody fragmentation; deproteinization; industrial enzyme preparations
I. Protease Concepts, Classification, and Key Control Variables
1.1 Classification Framework and Selection Logic in Research
(1) By cleavage mode
Endoproteases: cleave internal peptide bonds within a protein, rapidly generating peptide fragments; they are the main workhorses for proteomics digestion and limited proteolysis.
Exoproteases: remove amino acids or short peptides sequentially from the N- or C-terminus; they are suited for terminal processing, end verification, and controlled stepwise degradation.
(2) By catalytic center and mechanism
Serine proteases: represented by trypsin, chymotrypsin, and subtilisin-like proteases.
Cysteine proteases: represented by papain; their activity is often sensitive to redox state and alkylation conditions.
Metalloproteases: require metal ions to activate water for catalysis; collagenase systems are representative and are readily affected by metal chelators.
Aspartic proteases: typically exhibit higher activity under acidic conditions; pepsin is a representative example.
(3) By optimal pH range
Acid proteases; neutral proteases; alkaline proteases. This classification directly determines buffer selection, material compatibility, and sample-stability strategies.
1.2 Key Variables Determining Cleavage Patterns and Reproducibility
(1) Substrate accessibility and conformational factors
① Peptide bonds in tightly folded regions are less accessible; flexible linkers and exposed loops are typically cleaved first.
② Disulfide bonds, glycosylation, membrane association, and aggregation can alter site exposure and reaction kinetics.
③ Denaturation, reduction, and alkylation can improve digestion uniformity, but may reduce the discriminatory power of limited proteolysis for structural differences.
(2) Reaction window: pH, temperature, time, and enzyme-to-substrate ratio
① pH controls the ionization of catalytic residues and the charge distribution of the substrate, thereby affecting activity and site selectivity.
② Temperature influences both reaction rate and enzyme stability; excessive temperatures can increase nonspecific cleavage and promote substrate aggregation.
③ Time and enzyme-to-substrate ratio jointly define the endpoint; over-digestion can reduce informative content and increase spectral complexity.
(3) Additives, inhibitors, and carryover effects
① Chelators can inhibit metalloproteases and may also affect stability in certain systems.
② Residual surfactants, denaturants, or organic solvents can alter activity and specificity.
③ Incomplete quenching can cause endpoint drift, undermining batch consistency and data comparability.
II. The Most Common Research Proteases and Their Typical Uses
2.1 Core Digestion Systems for Proteomics and Protein Sequencing
(1) Trypsin
Trypsin preferentially cleaves peptide bonds C-terminal to lysine and arginine residues and is the standard protease for proteomics. Its strengths include highly regular cleavage rules, mature database-search strategies, and strong cross-batch comparability. Compact structures or heavily modified regions often require denaturation/reduction/alkylation, compatible surfactant systems, or pre-digestion strategies to improve coverage.
① Typical uses: standard LC–MS/MS digestion; peptide mapping; establishment of comparable peptide sets for quantitative proteomics.
② Key controls: missed-cleavage rate, peptide-length distribution, sequence coverage; compatibility between quenching and desalting workflows.
③ Representative trypsin products:
Catalog No. | Product Name | Grade and Purity |
Trypsin, Human Pancreas | Bioactive, Native, ≥95%(SDS-PAGE), Pre-lyophilization Protein Concentration | |
Trypsin from bovin pancreas | EnzymoPure™, potency ≥3000 units/mg | |
Trypsin from bovine pancreas | USP, ≥2,500 USP units/mg solid | |
Trypsin from bovine pancreas | EnzymoPure™, ≥180 units/mg protein | |
Trypsin from bovine pancreas | ActiBioPure™, GMP, Bioactive, EnzymoPure™, High Performance, >450 USP U/mg powder | |
Trypsin from bovine pancreas | ActiBioPure™, Bioactive, GMP, High Performance, EnzymoPure™, >4000 USP unit/mg pro. | |
Trypsin from bovine pancreas | essentially salt-free, lyophilized powder, ≥10,000 BAEE units/mg protein | |
Trypsin from bovine pancreas(0.22 μm,Filtered) | ≥180 units/mg protein (10,350 BAEE/3,450 USP/NF units/mg protein) | |
Trypsin from bovine pancreas(2X,Sterile,Irradiated) | ≥180 units/mg protein (10,350 BAEE/3,450 USP/NF units/mg protein) | |
Trypsin from bovine pancreas(TPCK Treated) | ≥180 units/mg protein (10,350 BAEE/3,450 USP/NF units/mg protein) | |
Trypsin from bovine pancreas(TPCK-Treated,Irradiated) | ≥180 units/mg protein | |
Trypsin from bovine pancreas(Modified,Sequencing Grade) | suitable for mass spectrometry (MS), ≥150 units/mg protein | |
Trypsin from bovine pancreas(Purified,Sequencing Grade II) | suitable for mass spectrometry (MS), ≥150 units/mg protein | |
Trypsin from porcine pancreas | Native, EnzymoPure™, ≥250 USP U/mg | |
Trypsin from porcine pancreas | BioReagent, for cell culture, lyophilized powder, 1,000-2,000 BAEE units/mg solid | |
Trypsin-EDTA | 0.25%，sterile, No Phenol Red | |
Trypsin/Lys-C Mix (MS) | Animal Free, Carrier Free, GMP, for protein sequencing, Recombinant, suitable for mass spectrometry (MS), ≥95%(SDS-PAGE) | |
Trypsin−Agarose | buffered aqueous suspension, from bovine pancreas trypsin | |
Trypsinogen from Bovine Pancreas | BioReagent, ≥85% | |
Trypsin | EnzymoPure™, 1:250，Tissue Culture Grade | |
Trypsin (MS) | Animal Free, Carrier Free, Recombinant, suitable for mass spectrometry (MS), ≥13000U/mg protein | |
Recombinant Heat-stableTrypsin | Animal Free, Carrier Free, GMP, Bioactive, Recombinant, ≥1000USP units/mg power; ≥2500USP units/mg protein | |
Recombinant Porcine Trypsin | Animal Free, Carrier Free, Bioactive, sterile-filtered, ≥90%, >10000 U/mg | |
Recombinant trypsin | EnzymoPure™, ≥3800 units/mg protein | |
Recombinant Trypsin | for protein sequencing, suitable for mass spectrometry (MS), ≥4500 units/mg | |
Recombinant Trypsin | EnzymoPure™, ≥2500 units/mg | |
Recombinant Trypsin Solution (W/O Phenol Red & EDTA) | BioReagent, for cell culture, sterile, 0.025 mg/mL | |
Recombinant Trypsin-EDTA Solution (W/O Phenol Red) | BioReagent, sterile, for cell culture, 0.025 mg/mL | |
Recombinant Trypsin-EDTA Solution (W/O Phenol Red) | BioReagent, for cell culture, sterile, 0.05 mg/mL | |
Recombinant Trypsin-EDTA Solution (with Phenol Red) | BioReagent, for cell culture, sterile, 0.025 mg/mL | |
Recombinant trypsin (cell culture grade) | Animal Free, Carrier Free, GMP, ≥95%(SDS-PAGE), ≥3800USP unit/mg pro. | |
Recombinant Trypsin (Pharmacopoeia Grade) | Animal Free, Carrier Free, GMP, ≥95%(SDS-PAGE), ≥3800USP unit/mg pro. |
(2) Lys-C
Lys-C primarily targets lysine sites and is often used as a pre-digestion step or as a complementary protease to trypsin to improve uniformity and coverage for structurally stable proteins or complex matrices.
① Typical uses: two-step digestion (Lys-C pre-digestion followed by trypsin); improved consistency for difficult samples.
② Key controls: fixed digestion order, standardized reaction conditions and quenching; internal controls to monitor cleavage-pattern drift.
③ Representative Lys-C products:
Catalog No. | Product Name | Grade and Purity |
Lys-C (MS) | Bioactive, Recombinant, suitable for mass spectrometry (MS), ActiBioPure™, EnzymoPure™, for protein sequencing, Animal Free, Carrier Free, ≥70%(HPLC), ≥3 U/mg protein | |
Trypsin/Lys-C Mix (MS) | Animal Free, Carrier Free, GMP, for protein sequencing, Recombinant, suitable for mass spectrometry (MS), ≥95%(SDS-PAGE) |
(3) Lys-N
Lys-N provides complementary cleavage behavior relative to trypsin at lysine-associated sites and can increase coverage by producing distinct peptide boundaries.
① Typical uses: complementary digestion; orthogonal validation in peptide mapping; improved detectability of difficult segments.
② Key controls: when combining enzymes, fix conditions and include internal controls.
③ Representative Lys-N products:
Catalog No. | Product Name | Grade and Purity |
Lys-N (MS) | Carrier Free, Bioactive, suitable for mass spectrometry (MS), Native, EnzymoPure™, for protein sequencing, ≥99.5%(HPLC), ≥300U/mg protein, from mushroom |
2.2 Proteases Commonly Used for Complementary Digestion and Structural Analysis
(1) Chymotrypsin
Chymotrypsin tends to cleave at sites associated with aromatic or hydrophobic residues and complements trypsin by improving coverage in hydrophobic regions and certain hard-to-observe segments.
① Typical uses: complementary digestion to increase coverage; domain-boundary validation; retrieval of hydrophobic peptides.
② Key controls: tighter time-window control to limit divergence of cleavage patterns; monitoring nonspecific cleavage and short-peptide fractions using controls.
③ Representative chymotrypsin products:
Catalog No. | Product Name | Grade and Purity |
α-Chymotrypsin from bovine pancreas | EnzymoPure™, ≥35 units/mg protein | |
α-Chymotrypsin from bovine pancreas | EnzymoPure™, 1000 usp u/mg | |
α-Chymotrypsin from bovine pancreas | EnzymoPure™, ≥45 units/mg protein | |
α-Chymotrypsin from bovine pancreas(TLCK Treated) | EnzymoPure™, ≥45 units/mg protein | |
α-Chymotrypsin from bovine pancreas(Purified) | EnzymoPure™, ≥45 units/mg protein | |
α-Chymotrypsin from porcine pancreas | EnzymoPure™, 1000 usp u/mg | |
α-Chymotrypsin from porcine pancreas | EnzymoPure™, 800 usp u/mg | |
Chymotrypsin from Bovine pancreas | ActiBioPure™, Bioactive, EnzymoPure™, Native, ≥1500 USP U/mg powder | |
Chymotrypsin from Porcine pancreas | ActiBioPure™, Bioactive, EnzymoPure™, Native, ≥1500 USP U/mg powder |
(2) Glu-C (V8 protease)
Glu-C is often used as a complement to trypsin to enhance sequence coverage and peptide-map information density, particularly when multidimensional cleavage evidence is required for structural or modification studies.
① Typical uses: complementary digestion; peptide mapping; domain-boundary validation.
② Key controls: fixed buffer system and time window to reduce cleavage-pattern drift.
③ Representative Glu-C products:
Catalog No. | Product Name | Grade and Purity |
Endoproteinase Glu-C (V8 Protease) (MS Grade) | Animal Free, Carrier Free, GMP, Bioactive, ActiBioPure™, EnzymoPure™, for protein sequencing, suitable for mass spectrometry (MS) |
(3) Asp-N
Asp-N complements trypsin in site selectivity, improving coverage and detectability of specific regions, and is used for protein sequencing and orthogonal peptide-map confirmation.
① Typical uses: complementary digestion to increase coverage; verification of engineered constructs and mutation-containing regions.
② Key controls: standardize multi-enzyme conditions and monitor batch consistency.
③ Representative Asp-N products:
Catalog No. | Product Name | Grade and Purity |
Asp-N (MS) | Animal Free, Carrier Free, Bioactive, ActiBioPure™, EnzymoPure™, for protein sequencing, suitable for mass spectrometry (MS), Recombinant, ≥97%(HPLC), ≥1800U/mg protein |
(4) Pepsin
Pepsin is highly active under acidic conditions and supports rapid digestion strategies at low pH. It can also provide evidence complementary to trypsin. Its specificity is relatively dispersed; its primary value lies in speed, condition compatibility, and controllable quenching.
① Typical uses: rapid acidic digestion; complementary digestion to improve coverage.
② Key controls: short time windows with rapid quenching; monitoring overly short-peptide fractions to maintain identification efficiency.
③ Representative pepsin products:
Catalog No. | Product Name | Grade and Purity |
Pepsin from Porcine Stomach | EnzymoPure™, ≥2,500 units/mg dry weight | |
Pepsin from porcine gastric mucosa | powder,≥400 units/mg protein | |
Pepsin from porcine gastric mucosa | powder，≥250 units/mg solid | |
Pepsin−Agarose from porcine gastric mucosa | lyophilized powder,≥30 units/mg dry solid | |
Pepsin | EnzymoPure™, 1：3000 | |
Pepsin | EnzymoPure™, ≥3000NF.U/mg | |
Pepsin | EnzymoPure™, ≥15000NF.units/mg | |
Recombinant Pepsin (MS Grade) | Animal Free, Carrier Free, GMP, Bioactive, ActiBioPure™, EnzymoPure™, for protein sequencing, suitable for mass spectrometry (MS), ≥20000 U/g Protein |
III. Tissue Dissociation, Deproteinization, and Specialty Cleavage Systems
3.1 Proteinase K
Proteinase K is a broad-spectrum, highly efficient endoprotease widely used for deproteinization in nucleic-acid preparation. The central goal is to remove protein contaminants and release nucleic acids, rather than to generate site-informative peptides.
(1) Typical uses
① Deproteinization for nucleic-acid extraction; removal of nuclease/protein-complex contamination; sample cleanup.
(2) Key controls
① Define inactivation/removal strategies to prevent residual activity from interfering with downstream enzymatic reactions or quantitative assays.
(3) Representative Proteinase K products
Catalog No. | Product Name | Grade and Purity |
Proteinase K | EnzymoPure™, lyophilized powder，≥30 units/mg protein | |
Proteinase K | EnzymoPure™, BioReagent | |
Proteinase K from Tritirachium album limber | EnzymoPure™, ≥20 units/mg dry weight | |
Proteinase K from Tritirachium album | EnzymoPure™, ≥500 units/mL, buffered aqueous glycerol solution |
3.2 Collagenase (commonly used for tissue dissociation)
Collagenase degrades collagen-related extracellular matrix components and is a standard tool for tissue digestion and cell isolation. In research practice, it is often combined with neutral proteases to improve dissociation efficiency while balancing cell viability and preservation of surface proteins.
(1) Typical uses
① Tissue digestion and cell isolation; matrix-degradation studies; processing of 3D culture systems.
(2) Key controls
① Different collagenase types have distinct substrate spectra; optimize combinations, dosage, and time windows based on tissue source and target cell type.
(3) Representative collagenase products
Catalog No. | Product Name | Grade and Purity |
Collagenase from Clostridium histolyticum(Animal Origin Free,A) | EnzymoPure™, ≥150 units/mg dry weight | |
Collagenase from Clostridium histolyticum(Animal Origin Free,B) | EnzymoPure™, ≥300 units/mg dry weight | |
Collagenase from Clostridium histolyticum(Animal Origin Free,C) | EnzymoPure™, ≥200 units/mg dry weight | |
Collagenase from Clostridium histolyticum(Type 1) | EnzymoPure™, ≥125 units/mg dry weight | |
Collagenase from Clostridium histolyticum(Type 2) | EnzymoPure™, ≥125 units/mg dry weight | |
Collagenase from Clostridium histolyticum(Type 3) | EnzymoPure™, ≥100 units/mg dry weight | |
Collagenase from Clostridium histolyticum(Type 4) | EnzymoPure™, Native, ≥160 units/mg dry weight | |
Collagenase from Clostridium histolyticum(Purified) | EnzymoPure™, Native, ≥500 units/mg dry weight | |
Collagenase + protease inhibitor | 2-5 FALGPA units/mg solid,≥800 CDU/mg solid |
3.3 Elastase
Elastase cleaves elastin-related substrates and is frequently used as an effector-enzyme model in inflammation, immunology, and tissue-injury studies. It can also serve as a complementary protease in protein processing workflows or for controlled degradation of specific substrates.
(1) Typical uses
① Mechanistic studies in inflammation; substrate/activity evaluation; complementary digestion or substrate-specific processing.
(2) Key controls
① Substrate preference and activity can vary substantially by elastase source; calibrate the system using standardized substrates.
(3) Representative elastase products
Catalog No. | Product Name | Grade and Purity |
Elastase from Human Neutrophil | ActiBioPure™, Bioactive, High Performance, EnzymoPure™, ≥95%(SDS-PAGE), Pre-lyophilization Protein Concentration | |
Elastase from porcine pancreas(Lyophilized) | EnzymoPure™, ≥3 units/mg protein | |
Elastase from porcine pancreas(Suspension) | EnzymoPure™, ≥3 units/mg protein | |
Elastase from porcine pancreas(Purified) | EnzymoPure™, ≥8 units/mg protein | |
Elastase, pancreatic from porcine pancreas | EnzymoPure™, 30 units/mg |
3.4 Subtilisin-like proteases (Bacillus subtilis/Bacillus licheniformis origin)
Subtilisin-like proteases exhibit cleavage patterns that are highly sensitive to pH, temperature, and substrate accessibility. In research, they are widely used for limited proteolysis to map domain boundaries, evaluate conformational stability differences, or assess condition sensitivity and system compatibility. In industry, they are commonly used for alkaline washing and removal of proteinaceous stains.
(1) Typical uses
① Limited proteolysis for domain mapping; conformational stability and condition-sensitivity assessment; validation of fragment-pattern consistency.
(2) Key controls
① Time-course sampling with rapid quenching; monitoring over-hydrolysis and nonspecific cleavage using SDS–PAGE or LC–MS.
(3) Representative subtilisin-like protease products
Catalog No. | Product Name | Grade and Purity |
Subtilisin from Bacillus licheniformis | technical grade, ≥200 U/mg powder | |
Proteinase, bacterial | Type XXIV, 7.0-14.0 units/mg solid, lyophilized powder | |
Protease from Bacillus licheniformis | lyophilized powder, for use in Total Dietary Fiber Assay, TDF-100A | |
Protease from Bacillus licheniformis | ≥2.4 U/g | |
Protease from Bacillus licheniformis | EnzymoPure™, ≥2.4 U/g | |
Protease(Subtilisin) | EnzymoPure™, 8 KNPU-E/g | |
Protease(Subtilisin) | EnzymoPure™, ≥3 AU-A/g | |
Protease (Subtilisin) | EnzymoPure™, 12 KNPU-S/g | |
Protease from Bacillus sp. | liquid, ≥16 U/g | |
Protease from Bacillus sp. | liquid, ≥16 U/g | |
Protease from Bacillus sp. | liquid, ≥8 U/g | |
Protease from Bacillus sp. | >1.5 AU-N/g | |
Protease from Bacillus sp. | EnzymoPure™, ≥16 U/g | |
Protease from Bacillus sp. | EnzymoPure™, ≥8 U/g | |
Protease from Bacillus amyloliquefaciens | EnzymoPure™, ≥0.8 U/g | |
Protease from Bacillus amyloliquefaciens | liquid, ≥0.8 U/g |
IV. Mechanism-Oriented Descriptions and Risk Control in Industrial and Application Settings
4.1 Leather, Fiber, and Detergent Systems
(1) Leather dehairing and softening
① Mechanism: controlled hydrolysis of hair-root and related structural proteins to achieve dehairing and softening.
② Process notes: control hydrolysis depth to avoid excessive degradation of leather matrix; manage salinity, pH, and temperature windows.
③ Risk control: manage dust/aerosol exposure; protect against skin contact and sensitization risks.
(2) Silk degumming
① Mechanism: selective removal of sericin to improve hand feel and dyeing/finishing consistency.
② Process notes: avoid damage to fibroin; control side reactions through time and temperature windows.
③ Quality focus: degumming ratio, tensile strength, and surface morphology.
(3) Enzymatic detergents for proteinaceous stain removal
① Mechanism: alkaline proteases hydrolyze protein-based soils (e.g., blood and sweat residues) to improve detergency.
② Formulation notes: ensure stability under alkaline conditions and in the presence of surfactants and oxidizing systems.
③ Safety note: avoid prolonged skin contact and inhalation of powders to reduce irritation and sensitization risk.
4.2 Food Processing and Baking Systems
(1) Meat tenderization, cheese production, and beverage clarification
① Mechanism: controlled hydrolysis alters molecular-weight distribution and solubility, thereby affecting texture and clarification performance.
② Process notes: avoid over-hydrolysis that increases bitter peptides or degrades structure.
③ Quality focus: soluble nitrogen, peptide distribution, and sensory evaluation.
(2) Plant-protein modification
① Mechanism: by controlling hydrolysis degree and product distribution, functional properties such as solubility, emulsification, and foaming can be tuned.
② Process notes: integrate pH, ionic strength, and heat-treatment effects on product distribution.
③ Quality focus: functional metrics and batch-to-batch consistency.
(3) Gluten network modulation and fermentation promotion in baking
① Mechanism: proteases modulate dough rheology by controlled hydrolysis of flour proteins, changing the three-dimensional gluten network—primarily by altering connectivity and chain integrity.
② Fermentation linkage: generated peptides and amino acids can serve as assimilable nitrogen sources for yeast, promoting fermentation.
③ Process notes: couple dosage with mixing intensity, fermentation time, and temperature to avoid excessive weakening of gluten structure and loss of mechanical support.
The shared essence of protease use in both research and industry is enzymatic hydrolysis that reshapes protein structural accessibility and molecular-weight distribution to enable analysis, processing, or functional modulation. In research, trypsin and complementary proteases (Lys-C, Lys-N, Glu-C, Asp-N, and chymotrypsin) form the core toolchain for proteomics and protein sequencing; pepsin supports rapid acidic digestion strategies; Proteinase K is used for deproteinization in nucleic-acid preparation; collagenase is central to tissue dissociation and matrix processing; and subtilisin-like proteases are widely used for limited proteolysis and condition-sensitivity assessment. Industrial applications further emphasize system compatibility, process control, and exposure-risk management. By defining target products, fixing reaction windows, standardizing quenching strategies, and establishing quantifiable quality-control metrics, the reproducibility and interpretability of protease-related experiments and processes can be substantially improved.
For more related articles, please see below:
[1] Papain (Papaya Cysteine Protease): Composition, Structure, Manufacturing, and Application Guidance
[2] Pepsin
[3] Pepsin——Structural Features, Enzymatic Properties, and Experimental Application Guide
[4] Selection Criteria for Proteinase K
[5] Comparison of Pharmacopoeial Standards for Trypsin and Recombinant Trypsin