Resumen
The preparation of a new stable and active form of chymotrypsin is described. The enzyme possesses the threonine 147 instead of alanine 149 as the NH2 terminal group of the C chain and has been called α1 chymotrypsin. The conformational transition that affects chymotrypsins at alkaline pH was investigated and compared with that of α- and δ chymotrypsins by studying the kinetic constants and their pH dependencies for the hydrolysis of various specific ester substrates. The k(cat) values obtained with α1 chymotrypsin are similar to those of α- and δ chymotrypsins. The K(m) values showed a progressive increase toward the alkaline pH region. The shape of the K(m) pH profiles closely resemble those of δ chymotrypsin and differ considerably from the behavior of α chymotrypsin. The results strongly implicate the participation of the alanine 149 amino group in the reversible inactivation of α chymotrypsin at high pH.
Idioma original | Inglés |
---|---|
Páginas (desde-hasta) | 4909-4914 |
Número de páginas | 6 |
Publicación | Journal of Biological Chemistry |
Volumen | 248 |
N.º | 14 |
Estado | Publicada - 1973 |
Áreas temáticas de ASJC Scopus
- Bioquímica
- Medicina (todo)
- Biología molecular
- Biología celular