This calc estimates the number of amino acid residues in a protein, enzyme or peptide from its molecular weight, assuming 120 g/mol per amino acid. Diameter is estimated from an empirical relationship.
This gives a useful estimate, but may be inaccurate, particularly for materials with unusual structures. As a reference, the molecularweight of Cytochrome C is 12 kDa, of hemoglobin is 68 kDa, and of glucose oxidase is 320 kDa (a dimer of 160 kDa strands).
