Palmer, C; Golden, Kerith D.; Daniels, L; Ahmad, H
Author Affiliation, Ana.
ACC deaminase from Issatchenkia occidentalis
Journal of Biological Sciences
Date of Publication
In this study ACC deaminase from Issatchenkia occidentalis was isolated, partially purified and characterized. 1-Aminocyclopropane-1-carboxylic acid (ACC) deaminase catalyzes the conversion of ACC to á-ketobutyric acid and ammonia. Most of the studies on this enzyme were done mainly from bacterial ACC deaminase; with only one reported nitrate utilizing yeast speices (Hansenula saturnus) A yeast which exhibited high ACC deaminase activity was isolated and identified as Issatchenkia occidentalis. Unlike Hansenula saturnus, it was non-nitrate utilizing and it did not utilize ammonium salts very well. The ACC deaminase from this yeast was inhibited by potassium cyanide, sodium borohydride and ACC-methyl ester all at 5mM. The cofactor pyridoxal-5-phosphate was not needed for activity. The enzyme is very liable in nature, losing half of its activity after one week and losing almost all of its activity after 2 weeks when stored at 13o C. Storage of the crude homogenate at -15o C prolonged its shelflife beyond 2 weeks. The enzyme displayed an optimum temperature and pH of 40o C and 7.5 respectively.....