Abstract
Taka-amylase A was reduced by sodium thioglycolate in 8M urea-0.01M EDTA to give an unfolded linear polypeptide containing nine sulfhydryl groups. The destruction of the molecular structure could be reversed by the removal of thioglycolate and urea, and by subsequent air-oxidation in appropriate conditions. The obtained reduced-oxidized Taka-amylase A had about half of the original enzymatic activity, and its various pro-perties approached to those of native Taka-amylase A. The reduced-oxidized Taka-amylase A was found to be a mixture of completely renatured Taka-amylase A and partially renatured Taka-amylase A. The former was isolated by crystallization, and its various properties coincided well with those of native Taka-amylase A. This finding suggests that the informations for the secondary and tertiary structures of Taka-amylase A are contained in its primary structure.
The authors wish to express their thanks to Sankyo Co. Ltd. for a supply of “Taka-diastase Sankyo”. This work was done during tenure of the post-doctoral fellowship of the Japanese Society for the Promotion of Science for one of the authors (T. T.).
