Aminopeptidase yscCo-II: a new cobalt-dependent aminopeptidase from yeast?purification and biochemical characterization
✍ Scribed by Herrera-Camacho, Irma; Morales-Monterrosas, Rosalva; Quir�z-Alvarez, Rub�n
- Publisher
- John Wiley and Sons
- Year
- 2000
- Tongue
- English
- Weight
- 142 KB
- Volume
- 16
- Category
- Article
- ISSN
- 0749-503X
No coin nor oath required. For personal study only.
✦ Synopsis
Me Âxico
Saccharomyces cerevisiae aminopeptidase yscCo-II (APCo-II) was puri®ed to apparent homogeneity by gel ®ltration, af®nity chromatography and anion-exchange chromatography. APCo-II is an hexameric cobaltdependent metallo-enzyme with an estimated native molecular mass of 290 kDa. Enzyme activity is only detected in the presence of cobalt ions at pH 7.0. Substrate speci®city studies indicate that aminopeptidase yscCo-II cleaves only basic N-terminal residues. PMSF, Cu 2+ , 1,10-phenanthroline and bestatin were found to be very strong inhibitors of aminopeptidase yscCo-II activity. Kinetic studies indicated that the enzyme has a similar K m and Ka Co (activation constant of cobalt) and, following extraction of cobalt from the enzyme, activity was recovered only after cobalt addition.