A program to calculate the isoelectric point of macromolecules.

A program containing 260 sentences, written in BASIC and adapted to be run in personal computers, has been developed to calculate isoelectric point values of macromolecules (proteins, nucleic acids, polysaccharides, etc.). This implies the calculation of the coefficients and roots of a particular kind of polynomial. With common personal computers and using a compiled version of the program, the time required to calculate pI values of macromolecules containing for example, 9, 12, and 18 acid-base residues with different pK values was around 10 s, 2 min, and 2 h respectively.