Abstract: A method is provided for the determination of the presence of a reverse transcriptase in a sample liquid. In an aqueous medium, at least an adenine ribopolynucleotide RNA template (poly A), an immobilized oligodeoxythyminenucleotide and a biotinylated deoxyuridine triphosphate are reacted in the presence of the sample liquid. After separation of the reacted and the unreacted biotinylated deoxyuridine triphosphate from each other, the reacted or the unreacted biotinylated deoxyuridine triphosphate is detected. Also provided is a method for the determination of infection of a patient to a retrovirus. The reaction is conducted in the presence of a sample body fluid and the reverse transcriptase. After the detection of the reacted or the unreacted biotinylated deoxyuridine triphosphate, the reverse-transcriptase-neutralizing and/or inhibiting antibody titer in the sample body fluid is determined.

Abstract: DNA having genetic information of a human plasma-type glutathione peroxidase h-p.multidot.GSHPx was identified and disclosed. The enzyme, h-p.multidot.GSHPx, is produced by the expression of said DNA genetic information by a transformant holding a vector into which said DNA is incorporated. The DNA and the transformant ensures efficient production of human plasma type h-p.multidot.GSHPx. The enzyme exhibits lipid peroxide extinction activity, and is considered to be useful for the treatment or the cure or the prevention of these diseases.

Abstract: DNA which encodes at least a polypeptide containing glutathione peroxidase activity and having an amino acid sequence from the N-terminal to the C-terminal of the formula: ##STR1## wherein * * * is selenocystein, is produced by culturing transformant host cells which possess extraneous DNA encoding a polypeptide with glutathione peroxidase activity in a medium containing selenium, and separating a thus-produced polypeptide with glutathione peroxidase activity from the cultured mass.

Abstract: An amino sugar compound represented by the general formula: ##STR1## (wherein m is an integer of 0 to 8, n is an integer of 1 to 8 and m+n is an integer of 1 to 8) has strong glycosidase inhibiting action and is produced by culturing an amino sugar compound producing microorganisms belonging to Streptomyces.