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Research Article
ACC Deaminase from Issatchenkia occidentalis

Clovis Palmer, Kerith Golden, Larry Danniels and Hanif Ahmad

ABSTRACT
In this study ACC deaminase from Issatchenkia occidentalis was isolated, partially purified and characterized. 1-Aminocyclopropane-1-carboxylic acid (ACC) deaminase catalyses the conversation of ACC to ?-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 species (Hansenula saturnus). A yeast which exhibited high ACC deaminase activity was isolated and was 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 5 mM. 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 13°C. Storage of the crude homogenate at -15°C prolonged its shelf life beyond 2 weeks. The enzyme displayed an optimum temperature and pH of 40°C and 7.5, respectively.
http://scialert.net/fulltext/?doi=jbs.2007.188.193&org=11

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