computePI {seqinr} | R Documentation

## To Compute the Theoretical Isoelectric Point

### Description

This function calculates the theoretical isoelectric point of a protein. Isoelectric point is the pH at which the protein has a neutral charge. These estimate does not account for the post-translational modifications.

### Usage

    computePI(seq)

### Arguments

`seq` | AA sequence as a vector of chars

### Value

It returns the pI.

### Note

Protein pI is calculated using pK values of amino acids described in Bjellqvist et al. See also `SEQINR.UTIL` for more details.

### Author(s)

D. Charif

### References

The algorithm is quite the same as the one which is implemented at the following url: http://www.expasy.org/tools/pi_tool-doc.html `citation("seqinr")`

### See Also

`SEQINR.UTIL`

### Examples

    ss = read.fasta(File=system.file("sequences/seqAA.fasta",package = "seqinr"),seqtype="AA")
    computePI(ss[[1]])

[Package seqinr version 1.0-4 Index]