Size/charge selectivity: The catalytic chamber selectively traps substrates via complementary electrostatic surfaces .
Processivity: Insulin is degraded without disrupting disulfide bonds, facilitated by IDE’s ability to stabilize substrate β-sheets while repositioning cleavage sites .
Conformational regulation: Mutations favoring the "open" conformation increase catalytic activity 40-fold .
Structural studies reveal that IDE activators (e.g., D10) stabilize substrate interactions at exosites, while inhibitors (e.g., BDM44768) block catalytic zinc coordination . Cryo-EM analyses demonstrate that IDE’s dynamic conformational changes enable substrate-assisted catalysis, particularly for amyloidogenic peptides .
Diabetes: IDE knockout mice exhibit glucose intolerance and insulin resistance .
Alzheimer’s disease: IDE deficiency correlates with Aβ accumulation, while its upregulation reduces amyloid plaques .
Cancer: Overexpression in neuroblastoma promotes proliferation, making IDE a potential oncology target .
Cryo-EM insights: IDE’s "tethered release" mechanism explains selective degradation of amyloidogenic peptides .
Substrate-assisted catalysis: Aβ stabilizes IDE’s disordered catalytic cleft, enhancing its own degradation .
Isoform-specific roles: The truncated isoform 2 may regulate full-length IDE activity, though its exact function remains unclear .
Insulin-Degrading Enzyme (IDE) is a zinc metallopeptidase responsible for degrading intracellular insulin, thereby ending its activity. It also contributes to intercellular peptide signaling by breaking down various peptides such as amylin, bradykinin, and kallidin. IDE's strong affinity for insulin leads to insulin-mediated inhibition of the degradation of other peptides like beta-amyloid. Impaired IDE function is associated with Alzheimer's disease and type 2 diabetes mellitus, although mutations in the IDE gene haven't been proven as a direct cause of these diseases. IDE is primarily found in the cytoplasm, but in certain cell types, it can also be located in the extracellular space, cell membrane, peroxisome, and mitochondrion. Moreover, IDE degrades amyloid generated by APP and IAPP and participates in the degradation and clearance of naturally secreted amyloid beta-protein by neurons and microglia.
IDE, filtered through a 0.4µm filter, is supplied in a solution of 20mM Tris buffer, 50mM NaCl, at pH 8.0, with 10% (w/v) glycerol.
IDE has two primary meanings in research contexts: Insulin-Degrading Enzyme, a metalloprotease involved in the clearance of insulin and amyloid-β peptides, and Industrial Design Engineering, a discipline focused on human-centered design research. Insulin-Degrading Enzyme plays a critical role in degrading various peptide hormones and has implications for conditions like Alzheimer's disease and diabetes. Industrial Design Engineering research at institutions like TU Delft focuses on themes of Health, Mobility, and Sustainability with perspectives on People, Technology, and Organisation .
Human Insulin-Degrading Enzyme consists of amino- and carboxy-terminal domains (IDE-N and IDE-C) that form an enclosed cage just large enough to encapsulate insulin and other peptide substrates. This unique structural arrangement creates a degradation chamber that remains inaccessible to substrates until the IDE domains reposition. The size and charge distribution of the substrate-binding cavity enable IDE to selectively entrap structurally diverse polypeptides. This explains IDE's remarkable capacity to cleave certain hormones selectively without degrading related family members .
For Insulin-Degrading Enzyme research, primary themes include investigating its role in:
Insulin clearance and glucose homeostasis
Amyloid-β degradation and Alzheimer's disease pathology
Processing of other bioactive peptides (amylin, glucagon)
Structural biology of substrate recognition and enzymatic action
For Industrial Design Engineering human research, key themes include:
Health: Human-centered design for healthcare solutions
Mobility: Design for sustainable transportation and movement
Sustainability: Environmentally conscious design approaches
Define inclusion and exclusion criteria for experiments before seeing the results
Preregister hypotheses and methods when conducting confirmatory research
Report all conducted experiments, even those with negative or inconclusive results
Clearly mark and disclose any post-hoc decisions for considering experiments as unreliable
Never use agreement with predictions or previous findings as criteria for including an experiment
This approach helps prevent the "file drawer effect" where inconvenient results remain unpublished and helps mitigate HARKing (Hypothesizing After Results are Known) .
When conducting structural studies of human IDE complexed with substrates, researchers should:
Implement predefined validation criteria for experimental outcomes
Establish clear parameters for what constitutes a successful experiment versus a methodological failure
Document all experimental attempts with both successful and unsuccessful outcomes
Validate findings across multiple substrates (e.g., insulin B chain, amyloid-β peptide, amylin, glucagon)
Correlate structural findings with functional assays to confirm biological relevance
These approaches ensure reproducibility and prevent bias in structural biology research on complex enzymes like IDE .
Based on successful approaches at TU Delft's Faculty of Industrial Design, researchers can map interconnections through:
Creating comprehensive surveys asking researchers to:
List expertise using specific keywords
Associate their research with fundamental platforms identified in the field
Identify collaborative networks
Developing visualizations of research interconnectedness showing:
Overlapping research interests
Cross-disciplinary collaborations
Thematic clusters within the broader research community
This mapping approach has proven valuable for both organizing research content and identifying collaborative opportunities within IDE research communities .
Human research involving IDE (either enzyme studies or industrial design engineering) requires careful consideration of:
Determination of whether the research requires IRB review (not all IDE research needs IRB approval)
Proper submission procedures through institutional HRPP (Human Research Protection Program)
Addressing data security and confidentiality concerns, particularly with sensitive biological samples or personal design research data
Understanding the distinctions between quality improvement activities and formal research
Ensuring appropriate consent processes when human participants are involved
Researchers should consult their institution's Investigator Manual or equivalent resource for specific guidance on navigating IRB requirements .
When working with human data or specimens in IDE research:
Determine whether secondary use research requires consent:
Consider the identifiability of samples/data
Assess the original consent parameters
Evaluate regulatory requirements for different specimen types
Establish protocols for sharing identifiable data or specimens with collaborators:
Material Transfer Agreements (MTAs) may be required
Data sharing agreements should address confidentiality
For biospecimens sent outside the institution:
Follow institutional policies for transfer
Ensure proper documentation and tracking
Address any intellectual property considerations
These considerations apply to both biological samples containing Insulin-Degrading Enzyme and human data collected during Industrial Design Engineering research .
Effective data and safety monitoring plans for IDE research should:
Establish clear validation criteria before experiments begin
Document all experimental attempts, even unsuccessful ones
Implement consistent data preprocessing pipelines, particularly for high-throughput studies
Set objective criteria for defining outliers or problematic data points
Create independent monitoring mechanisms when appropriate
These measures help prevent post-hoc rationalization of experimental failures and reduce researcher bias in data interpretation and reporting .
When incorporating AI tools in IDE human research, researchers should consider:
Potential issues during submission:
Data security concerns
Limitations of AI data entry
Copyright considerations
For intervention-based research with AI tools:
Provide detailed information about AI mechanisms
Address potential biases in AI algorithms
Document validation procedures for AI outputs
Participant information requirements:
Clear disclosure about AI involvement
Explanation of data usage and privacy safeguards
Description of limitations in AI-based interventions
These considerations ensure ethical integration of AI tools while maintaining scientific rigor in IDE research .
Human IDE's unique structural features contribute to its remarkable substrate selectivity through:
Formation of an enclosed catalytic chamber:
IDE-N and IDE-C domains create a cage-like structure
The chamber size is precisely calibrated to fit insulin and similar-sized peptides
Substrate access mechanism:
Repositioning of IDE domains controls substrate entry
Extensive contacts between domains regulate access to the degradation chamber
Selective substrate entrapment:
Size and charge distribution within the binding cavity enable recognition of diverse polypeptides
This explains IDE's ability to selectively cleave certain hormones while sparing related family members
This structural arrangement allows IDE to perform its biological functions with specificity despite the diversity of its substrates .
To effectively study IDE-substrate interactions, researchers should:
Employ multiple complementary techniques:
X-ray crystallography for static structural analysis
Molecular dynamics simulations for understanding conformational changes
Biochemical assays for enzyme kinetics and substrate preference
Analyze multiple substrate types:
Include diverse peptides (insulin B chain, amyloid-β, amylin, glucagon)
Compare binding and cleavage patterns across substrate families
Investigate both binding and catalytic events:
Study initial substrate recognition
Analyze intermediate steps in the degradation process
Examine product release mechanisms
This comprehensive approach provides deeper insights into IDE's selective yet broad substrate recognition capacity .
IDE was first identified over sixty years ago due to its ability to degrade the B chain of insulin . The enzyme responsible for this activity was later identified and characterized. The discovery of IDE’s role in insulin degradation has significant implications for understanding insulin regulation and its termination of activity in insulin-responsive tissues .
IDE is composed of two homologous ~55 kDa N- and C-terminal halves, which form a large opening that allows selective substrate capture based on size and charge complementarity . This structural feature is crucial for IDE’s ability to degrade amyloidogenic peptides, including insulin and amyloid β-protein (Aβ), which are associated with type 2 diabetes mellitus and Alzheimer’s disease .
IDE degrades insulin by stochastically cutting either chain without breaking disulfide bonds . This processive degradation is facilitated by the enzyme’s catalytic cleft, which is stabilized by amyloidogenic peptides through substrate-assisted catalysis . The enzyme’s ability to degrade various peptides, such as amylin, bradykinin, and kallidin, highlights its role in intercellular peptide signaling .
The human recombinant form of IDE has been successfully expressed in Chinese hamster ovary cells using a plasmid containing the IDE cDNA under the transcriptional control of the SRα promoter . The recombinant protein synthesized by these cells is indistinguishable from the isolated human enzyme in both size and immunoreactivity, and it degrades insulin with a specific activity similar to that of the purified proteinase .
IDE’s role in degrading insulin and amyloidogenic peptides makes it a potential therapeutic target for diseases such as type 2 diabetes and Alzheimer’s disease . Understanding the molecular basis of IDE’s function and its interaction with substrates can aid in the development of IDE-based therapies .