Pentose Metabolism in Candida utilis

l-Arabinose ketol isomerase (EC 5.3.1.4) was extracted from cells of Candida utilis which were grown in sulfite pulp mill waste.The enzyme was partially purified 135-fold by means of fractionation with ammonium sulfate, on DEAE-cellulose and DEAE-Sephadex A-50 column chromatographies and gel filtration on Sephadex G-200.Optimal pH and temperature for the activity of the enzyme were 7.0 and 60°C, respectively. The enzyme reaction was activated by Co2+ and Mn2+, and was inhibited by Na-pyrophosphate.The Michaelis-Menten’s constant for l-arabinose was 1.07×10−1m, and the thermodynamic quantities, ΔH, ΔG (35°C), ΔS (35°C) and E were 8914 cal/mole, −1397 cal/mole, 33.5 cal/deg mole and 9588 cal/mole, respectively.