A thermostable and detergent-stable α-amylase from a newly isolated Anoxybacillus sp. AH1 was purifi ed and characterized. Maximum enzyme production (1874.8 U/mL) was obtained at 24 h of incubation. The amylase was purified by using Sephadex G-75 gel filtration, after which an 18-fold increase in specific activity and a yield of 9 % were achieved. The molecular mass of the purified enzyme was estimated at 85 kDa by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). The optimum pH and temperature values of the enzyme were 7.0 and 60 °C, respectively. The enzyme was highly stable in the presence of 30 % glycerol, retaining 85 % of its original activity at 60 °C within 120 min. Km and vmax values were 0.102 μmol and 0.929 μmol/min, espectively, using Lineweaver-Burk plot. The enzyme activity was increased by various detergents, but it was significantly inhibited in the presence of urea. Mg2+ and Ca2+ also significantly activated α-amylase, while Zn2+, Cu2+ and metal ion chelators ethylenediaminetetraacetic acid (EDTA) and 1,10-phenanthroline (phen) greatly inhibited the enzyme activity. α-Amylase activity was enhanced by β-mercaptoethanol (β-ME) and dithiothreitol (DTT) to a great extent, but inhibited by p-chloromercuribenzoic acid (PCMB). Iodoacetamide (IAA) and N-ethylmaleimide (NEM) had a slight, whereas phenylmethylsulfonyl fluoride (PMSF) had a strong inhibitory effect on the amylase activity.U radu je pročišćena i okarakterizirana α-amilaza, izolirana iz novootkrivenog soja bakterije Anoxybacillus sp. AH1, stabilna pri visokim temperaturama u prisutnosti detergenata. Najveća količina enzima (1874,8 U/mL) proizvedena je nakon 24 sata inkubacije. Nakon pročišćavanja amilaze gel-filtracijskom kromatografijom u koloni punjenoj gelom Sephadex G-75, specifična se aktivnost enzima povećala 18 puta, a prinos je bio 9 %. Metodom SDS-PAGE određena je molekularna masa pročišćenog enzima od 85 kDa. Optimalna je pH-vrijednost bila 7,0; a optimalna temperatura 60 °C. Enzim je bio izuzetno stabilan u prisutnosti 30 %-tnog glicerola, te je zadržao 85 % aktivnosti na 60 °C tijekom 120 min. Pomoću Lineweaver-Burkovog dijagrama utvrđeno je da je vrijednost Km amilaze bila 0,102 μmol, a vmax 0,929 μmol/min. Aktivnost se enzima povećala u prisutnosti različitih detergenata, dok se u prisutnosti uree znatno smanjila. Ioni magnezija i kalcija bitno su povećali, a ioni cinka i bakra, te kelatori metalnih iona EDTA i 1,10-fenantrolin smanjili aktivnost α-amilaze. Aktivnost se α-amilaze znatno povećala i u prisutnosti β-merkaptoetanola i ditiotreitola, no smanjila dodatkom p-kloromerkuribenzojeve kiseline. Jodoacetamid i N-etilmaleimid imali su blag, a fenilmetilsulfonil fluorid jak inhibicijski učinak na aktivnost amilaze
