Abstract: The present invention provides a versatile mutant reverse transcriptase with high thermal stability, a nucleic acid thereof and a method for producing a mutant reverse transcriptase, a versatile kits for reverse transcription and detection, a method for improving thermal stability of a nucleic acid-related enzyme, which significantly improves thermal stability of a nucleic acid-related enzyme, and a reverse transcription method, which efficiently performs a reverse transcription. An amino acid residue in a nucleic acid interaction region of a wild-type enzyme is substituted with a positively-charged amino acid residue or a nonpolar amino acid residue, to form a nucleic acid interaction region having a positive effective charge larger than the nucleic acid interaction region of a wild-type enzyme.

Abstract: The present invention provides a versatile mutant reverse transcriptase with high thermal stability, a nucleic acid thereof and a method for producing a mutant reverse transcriptase, a versatile kits for reverse transcription and detection, a method for improving thermal stability of a nucleic acid-related enzyme, which significantly improves thermal stability of a nucleic acid-related enzyme, and a reverse transcription method, which efficiently performs a reverse transcription. An amino acid residue in a nucleic acid interaction region of a wild-type enzyme is substituted with a positively-charged amino acid residue or a nonpolar amino acid residue, to form a nucleic acid interaction region having a positive effective charge larger than the nucleic acid interaction region of a wild-type enzyme.

Abstract: A method for separating immunoglobulin G subclasses, which comprises separating immunoglobulin G subclasses by liquid chromatography by using as the solid phase a porous gel having an exclusion limit molecular weight larger than the molecular weight of immunoglobulin G, as calculated as protein, and a buffer solution having an ionic strength of from 0.1 to 2.0M.