Isotope Coded Affinity Tags | ICAT | Non-Gel Based Proteomics | Dr. Nagendra Singh | PENS#108

Item: Isotope Coded Affinity Tags | ICAT | Non-Gel Based Proteomics | Dr. Nagendra Singh | PENS#108
Rating: 4
Author: PostSingularity Institute

by Prof. Nagendra Singh

Life & Natural Systems Biology PSBiology, life sciences PSBBiochemistry

🎙 Prof. Nagendra Singh 👥 5K 📅 April 21, 2026 ⏱ 10 min 👁 306 📄 tutorial 🧭 2026-08-16

Available in: English (current) Français

Keywords

ICATisotope labelingquantitative proteomicscysteinemass spectrometry

Summary

This technical lecture by Prof. Nagendra Singh introduces Isotope-Coded Affinity Tags (ICAT), a gel-free quantitative proteomics method. The ICAT reagent consists of three components: a biotin tag for affinity purification, a thiol-reactive group (iodoacetamide) that covalently binds to cysteine residues, and a linker with eight hydrogen positions that can be either light (H) or heavy (deuterium). The workflow involves differential labeling of proteins from two samples (e.g., normal vs. diseased), mixing, tryptic digestion, avidin affinity chromatography to enrich labeled peptides, and LC-MS/MS analysis. Quantification is achieved by comparing the light-to-heavy (L/H) ratios of peptide pairs in the mass spectra, which differ by 8 Da. The method reduces sample complexity by targeting cysteine-containing peptides, offers high sensitivity and broad applicability, and is suitable for disease research and drug target identification. However, it has limitations: it is biased toward cysteine-containing proteins, and it provides relative rather than absolute quantification.

147 words

Critical Evaluation

Value of the Information & Strength of the Argument

The lecture provides a clear and detailed explanation of the ICAT technique, covering its chemical basis, workflow, and data interpretation. The argumentation is logical and well-structured, with step-by-step reasoning from labeling to quantification. The value lies in its educational clarity, making a complex technique accessible. The explanation of the mass difference and peak intensity ratio is particularly effective for understanding relative quantification. The pros and cons are briefly mentioned, but a deeper comparison with alternative methods like iTRAQ or SILAC would enhance the argumentation.

93 words

Title / Content Match

The title accurately reflects the content, which focuses on ICAT as a non-gel-based proteomics technique.

Quality & Reliability

8/10

The lecture is technically accurate and well-structured, explaining the ICAT method with clear steps and mechanisms. The content aligns with established proteomics knowledge, though it lacks citations to primary literature.

Key Moments

Markers derived by PSI from the transcript: the creator did not define chapters.

Concurring Sources

Isotope-coded affinity tag - Wikipedia — Provides background and details on ICAT, consistent with the lecture.

Contribution & Novelties

The lecture provides a clear pedagogical explanation of ICAT, a foundational technique in quantitative proteomics. It effectively breaks down the reagent structure and workflow, making it accessible to learners. The discussion of advantages and limitations is concise but informative.

Pour aller plus loin :

Isotope-coded affinity tag - Wikipedia — Overview and history of ICAT.
Stable isotope labeling by amino acids in cell culture (SILAC) - Wikipedia — Alternative quantitative proteomics method.
Isobaric tags for relative and absolute quantitation (iTRAQ) - Wikipedia — Another labeling technique for comparison.

88 words

Radar Profile

The radar profile shows high scores in information quantity, quality, and reliability, with a slightly lower technical level. This indicates a well-balanced educational resource that is both informative and trustworthy, though it may not delve into advanced technical nuances.

Reliability 8/10