title: A thermostable D-hydantoinase isolated from a mesophilic Bacillus sp.AR9.
abstract: A thermostable hydantoinase has been characterized from a mesophilic Bacillus sp.AR9. The hydantoinase produced by this Bacillus sp.AR9 is strictly D-specific and is constitutively produced with high yields (4500 U/ml) in this strain. The enzyme is not only alkalo- and thermostable but has a pH and temperature optimum of 9.5 and 65 degrees C, respectively, which is advantageous for the bioconversion of DL-5-monosubstituted-hydantoin derivatives. The enzyme has a half life of 80 minutes at 70 degrees C and loses only 33% of its activity in 4 hr at 60 degrees C. The enzyme has a broad substrate specificity with a maximum of 100% with hydantoin and about 26% with dihydrouracil. Co+ + ions enhance the activity of the enzyme by more than 60%.
authors.affiliation: Biochemical Engineering Research and Process Development Centre, Institute of Microbial Technology, Chandigarh, India.
authors.forename: R
authors.initials: R
authors.lastname: Sharma
authors.forename: R M
authors.initials: RM
authors.lastname: Vohra
mesh_terms: D000581:Amidohydrolases / Q000302:isolation & purification* / Q000378:metabolism*; D001407:Bacillus / Q000201:enzymology*; D002413:Cations, Divalent / Q000494:pharmacology; D003035:Cobalt / Q000494:pharmacology; D004789:Enzyme Activation / Q000187:drug effects; D004795:Enzyme Stability; D006207:Half-Life; D006827:Hydantoins / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D013237:Stereoisomerism; D013379:Substrate Specificity; D013696:Temperature
chemical_list: D002413:Cations, Divalent; D006827:Hydantoins; D003035:Cobalt; D000581:Amidohydrolases; C020047:dihydropyrimidinase