Novel protease variants derived from the DNA sequences of naturally-occurring or recombinant non-human proteases are disclosed. The variant proteases, in general, are obtained by in vitro modification of a precursor DNA sequence encoding the naturally-occurring or recombinant protease to generate the substitution of a plurality of amino acid residues in the amino acid sequence of a precursor protease. Protease variants are provided that contain substitutions of the amino acids at one or more residue positions so that the substitution alters the charge at that position to make the charge more negative or less positive compared to a precursor protease and thus the protease variant is more effective in a low detergent concentration system than a precursor protease. Also provided are protease variants containing substitutions of the amino acids at one or more residue positions so that the substitution alters the charge at that position to make the charge more positive or less negative compared to a precursor protease and thus the protease variant is more effective in a high detergent concentration system than a precursor protease. Protease variants are provided that contain substitutions of the amino acids at one or more residue positions so that the substitution alters the charge at that position to make the charge more negative or less positive compared to a precursor protease and thus the protease variant is more effective in a medium detergent concentration system than a precursor protease. Also provided are protease variants containing substitutions of the amino acids at one or more residue positions so that the substitution alters the charge at that position to make the charge more positive or less negative compared to a precursor protease and thus the protease variant is more effective in a medium detergent concentration system than a precursor protease. Further provided is a method of producing a protease variant that is more effective in a low detergent concentration system, medium detergent concentration system and high detergent concentration system than a precursor protease.