How to Determine the Molecular Weight and Amino Acid Residues of a Protein? Is Experimental Detection Necessary?
To determine the molecular weight and number of amino acid residues of a protein, there are several approaches and methods: querying public databases, using tools, and experimental detection.
Using Bioinformatics Tools and Databases
1. Database Search
If the protein sequence is known, you can search for its molecular weight and amino acid sequence information in public protein databases, such as UniProt, NCBI's Protein Database, and PDB (Protein Data Bank). These databases typically list known proteins' molecular weight, amino acid residues count, functional information, and other related data.
2. Sequence Analysis Tools
Using tools like ExPASy's ProtParam, you can input the protein’s amino acid sequence, and the tool will automatically calculate the protein's molecular weight and number of amino acid residues.
Experimental Detection
If the protein sequence is unknown or you need more accurate experimental data, the following techniques can be used:
1. Mass Spectrometry (MS)
MS can not only identify proteins but also precisely determine their molecular weight. After digesting the protein into peptides, MS provides mass information for the peptides, which can be used to deduce the protein's molecular weight. By matching with protein databases, the amino acid residue sequence can also be identified.
2. SDS-PAGE
SDS-PAGE can be used to estimate the molecular weight of a protein. After loading the protein sample and performing electrophoresis, the protein’s migration rate in the gel can be compared with molecular weight markers to roughly estimate its molecular weight.
3. Edman Degradation
This method is used to determine the amino acid sequence of a protein by sequentially removing and identifying the amino acid residues at the N-terminus through chemical reactions.
If you have the protein's sequence information, molecular weight and amino acid residue count can be directly retrieved from databases and online tools. If the sequence is unknown or experimental verification is required, techniques such as mass spectrometry, SDS-PAGE, or Edman degradation can be employed.
MtoZ Biolabs, an integrated chromatography and mass spectrometry (MS) services provider.
Related Services
How to order?
