Resources

Proteomics Databases



Metabolomics Databases

• • A Complete Guide to Label-Free Quantitative Proteomics (LFQ) in Biomedical Research

  In the post-genomic era, genetic information alone is insufficient to capture the dynamic regulation of biological processes. Proteins, as the primary effectors of gene function, directly reflect the functional state of cells. To comprehensively monitor protein expression dynamics, proteomics technologies have emerged. Among them, Label-Free Quantitative Proteomics (LFQ) stands out for its label-free nature, flexible sample handling, and scalability, making it widely applicable across biomedical research...

• • Applications of LC-MS/MS in Label-Free Quantitative Proteomics

  LC-MS/MS: A Foundational Technology for Label-Free Quantification Label-Free Quantification (LFQ) has emerged as one of the predominant strategies in modern proteomics, largely driven by advances in LC-MS/MS technology. LC-MS/MS integrates liquid chromatography (LC) and tandem mass spectrometry (MS/MS), where LC efficiently separates complex peptide mixtures, and MS/MS subsequently performs both qualitative identification and quantitative analysis. In LFQ, the signal intensity at the MS1 level—specifically

• • Label-Free vs. Label-Based Quantitative Proteomics: Which One to Choose?

  In proteomics research, the choice of quantitative strategy directly influences the resolution, reliability, and breadth of application of the experiment. Given the diversity of sample types and research objectives, researchers often face difficulties in deciding between Label-Free Quantitative Proteomics (Label-Free) and Label-Based Quantitative Proteomics (Labeling, such as TMT or iTRAQ). This article provides a comprehensive comparison of these two major approaches—examining their underlying principles..

• • Label-Free Quantitative Proteomics (LFQ): Technology, Applications, and Advances

  Introduction: Why Are More and More Researchers Choosing LFQ? In proteomics research, quantification goes beyond merely determining the presence or absence of proteins; it involves accurately characterizing changes in protein expression under varying physiological or pathological conditions. While traditional isotope labeling techniques such as TMT and iTRAQ offer high sensitivity, they are often limited by high costs and complex experimental workflows. In contrast, Label-Free Quantification (LFQ) has .....

• • Revealing Protein Structure through Circular Dichroism Spectroscopy

  Proteins play essential roles in living organisms, with their function intricately tied to their structure. Circular dichroism (CD) spectroscopy offers valuable insights into protein structures.    Principles of Circular Dichroism (CD) Spectroscopy CD spectroscopy analyzes samples by measuring the optical rotation properties of light. When linearly polarized light encounters chiral molecules, its polarization direction rotates, creating an effect known as optical rotation. This property allows CD spec......

• • How Does Circular Dichroism Reveal Protein Conformational Diversity

  The function of a protein is closely related to its conformation, which is influenced by its secondary structure, folding state, and conformational changes. So, how does circular dichroism reveal the diversity of protein conformations?   The Principle of Circular Dichroism Circular dichroism (CD) studies protein conformation by measuring its absorption of circularly polarized light. Circularly polarized light is a type of polarized light with a specific rotation direction, and when protein molecules a......

• • What Are the Applications of Circular Dichroism in Protein Research

  Circular dichroism (CD) leverages the optical rotation occurring when circularly polarized light interacts with chiral molecules to study their structures. As circularly polarized light passes through these molecules, the direction of light rotation changes—a phenomenon called optical rotation. CD measures differences in light absorption to produce signals that reveal structural characteristics of the sample.   1. Protein Structure Analysis CD provides insights into the secondary structures of protein......

• • The Secrets to Biomolecular Composition: What Does Circular Dichroism Spectroscopy Reveal

  Biomolecules are the essential building blocks of life, yet deciphering their structure and composition remains challenging. Circular dichroism (CD) spectroscopy allows researchers to study molecular structures by measuring how molecules absorb circularly polarized light. By examining CD spectra, scientists can gain detailed insights into the secondary structures, chiral properties, and stereochemistry of biomolecules, which provides valuable clues for understanding their functions and interactions.  ......

• • How to Measure the Extinction Coefficient?

  The extinction coefficient refers to a substance's ability to absorb light at a given concentration. It is related to the molar absorptivity of the substance and the path length. The molar absorptivity indicates the substance's ability to absorb light at a unit molar concentration, while the path length represents the distance light travels through the solution. The extinction coefficient can be calculated as the product of the molar absorptivity and path length. In the field of biopharmaceutical anal......

• • De Novo Sequencing Sample Quantity

  De novo sequencing, also known as sequencing from scratch, is a method used for sequence analysis of proteins or peptides, particularly suitable for analysis in the absence or incompleteness of reference sequences. This technique primarily relies on mass spectrometry (MS) data to infer the original sequence of proteins or peptides by analyzing the mass spectra fragmentation patterns of peptide ions.