Characterization of chitinases of polycentric anaerobic rumen fungi.
Chitinolytic systems of anaerobic polycentric rumen fungi of genera Orpinomyces and Anaeromyces were investigated in three crude enzyme fractions - extracellular, cytosolic and cell-wall. Endochitinase was found as a dominant enzyme with highest activity in the cytosolic fraction. Endochitinases of both genera were stable at pH 4.5-7.0 with optimum at 6.5. The Orpinomyces endochitinase was stable up to 50 degrees C with an optimum for enzyme activity at 50 degrees C; similarly, Anaeromyces endochitinase was stable up to 40 degrees C with optimum at 40 degrees C. The most suitable substrate for both endochitinases was fungal cell-wall chitin. Enzyme activities were inhibited by Hg(2+) and Mn(2+), and activated by Mg(2+) and Fe(3+). Both endochitinases were inhibited by 10 mmol/L SDS and activated by iodoacetamide.
Novotná
Z
Z
Institute of Animal Physiology and Genetics, v.v.i., Academy of Sciences of the Czech Republic, 142 20 Prague, Czechia. novotna@iapg.cas.cz
Fliegerová
K
K
Simůnek
J
J
D000693:Anaerobiosis; D000818:Animals; D002686:Chitin / Q000378:metabolism*; D002688:Chitinases / Q000737:chemistry / Q000378:metabolism; D008411:Chytridiomycota / Q000145:classification / Q000201:enzymology* / Q000254:growth & development; D004795:Enzyme Stability; D005656:Fungal Proteins / Q000235:genetics; D006863:Hydrogen-Ion Concentration; D020085:Neocallimastigales / Q000145:classification / Q000201:enzymology* / Q000254:growth & development; D012417:Rumen / Q000378:metabolism / Q000382:microbiology*; D013696:Temperature
D005656:Fungal Proteins; D002686:Chitin; D002688:Chitinases