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Expasy Protein Molecular Weight Calculation:
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The Expasy Protein Molecular Weight Calculator estimates the molecular weight of a protein from its amino acid sequence. It uses the monoisotopic masses of individual amino acids to calculate the total molecular weight in daltons (Da).
The calculator uses the following formula:
Where:
Explanation: The calculator sums the monoisotopic masses of all amino acids in the protein sequence to determine the total molecular weight.
Details: Knowing a protein's molecular weight is essential for various applications including protein purification, electrophoresis, mass spectrometry analysis, and biochemical characterization.
Tips: Enter the protein amino acid sequence using single-letter codes. The calculator will automatically remove any non-amino acid characters and calculate the molecular weight based on the remaining valid sequence.
Q1: What are monoisotopic masses?
A: Monoisotopic mass is the mass of a molecule calculated using the mass of the most abundant isotope of each element.
Q2: Does this calculator account for post-translational modifications?
A: No, this calculator provides the molecular weight of the unmodified amino acid sequence only.
Q3: What about N-terminal methionine cleavage?
A: This calculator does not account for potential processing events. It calculates the molecular weight of the exact sequence provided.
Q4: Are disulfide bonds considered in the calculation?
A: No, the calculator only considers the amino acid sequence without accounting for disulfide bond formation or other structural features.
Q5: How accurate is this calculation?
A: The calculation provides a theoretical molecular weight based on amino acid composition. Actual experimental values may vary slightly due to various factors.