Physico-chemical Characterization of Tyrosyl Residues in α-Chymotrypsinogen and π-Chymotrypsin
1965 年 58 巻 1 号 p. 60-67
詳細
1965 年 58 巻 1 号 p. 60-67
1. The activation energy of tryptic activa-tion of a-chymotrypsinogen was obtained by the enzyme assay and ultraviolet absorption spectral change. The values obtaind by the two methods were fairly in good agreement.
2. The spectrophotometric titration on both α-chymotrypsinogen and π-chymotrypsin revealed that two out of the total four tyrosyl titratable.
3. Two exposed tyrosyl residues were easily iodinated both in π-chymotrypsin and a-chymotrypsinogen. Iodinated samples were in full activity or activatability.
4. Two exposed tyrosyl residues were easily modified with FDNB. Since the spectral change observed during the tryptic activation of DNP-chymotrypsinogen was the same as that observed in tryptic activation of a-chymotrypsinogen, this spectral change was attributed to the environmental change of the hurried tyrosyl residue.
