distance between amino acids and sequences

[Lev Zhivotovsky]

Dear colleagues,

Would you please let me know what's known about how to calculate distance
between two amino acids based on biochemical properties of the molecules ?

Additional question then is how to compute distance between two amino acid
sequencies of equal length that differ from each at several positions.

Is there any computer program to get the distance matrix for a set of amino
acid sequences ?

Thank you in advance,

Lev Zhivotovsky