Provided are a polypeptide having a glycine-glycine bond-degrading activity and an improved microbicidal activity, and a method for using the same. A polypeptide consisting of the amino acid sequence of SEQ ID NO: 2 or an amino acid sequence having at least 80% identity thereto, the polypeptide having any modification selected from the group consisting of: a modification of an amino acid residue at position 116 in the amino acid sequence of SEQ ID NO: 2 or a position corresponding thereto; a modification of amino acid residues at position 170 in the amino acid sequence of SEQ ID NO: 2 or a position corresponding thereto, position 172 or a position corresponding thereto, position 173 or a position corresponding thereto, position 174 or a position corresponding thereto, position 178 or a position corresponding thereto, and position 179 or a position corresponding thereto; a modification of amino acid residues at position 170 in the amino acid sequence of SEQ ID NO: 2 or a position corresponding thereto, position 172 or a position corresponding thereto, position 173 or a position corresponding thereto, and position 174 or a position corresponding thereto; and a modification of amino acid residues at position 116 in the amino acid sequence of SEQ ID NO: 2 or a position corresponding thereto, position 170 or a position corresponding thereto, position 172 or a position corresponding thereto, position 173 or a position corresponding thereto, position 174 or a position corresponding thereto, position 178 or a position corresponding thereto, and position 179 or a position corresponding thereto, and the polypeptide having a glycine-glycine bond-degrading activity.

Provided are a rigid surface treatment agent capable of imparting an antibacterial property to a rigid surface, and a method for treating a rigid surface using the rigid surface treatment agent. The rigid surface treatment agent comprises, as an active component, a polypeptide which consists of an amino acid sequence of SEQ ID NO: 2, or a polypeptide which consists of an amino acid sequence having an identity of at least 80% with the amino acid sequence of SEQ ID NO: 2, and has activity of degrading a glycine-glycine bond in a peptide sequence.