Temperature selects for static soil enzyme systems to maintain high catalytic efficiency

摘要: Abstract Knowledge on enzymatic mechanisms of acclimation to temperature is required predict the effects warming decomposition soil organic matter – largest C stock in terrestrial ecosystems. Based Michaelis–Menten kinetics we tested hypothesis that enzyme affinity substrate (Km) more sensitive at cold than warm temperatures. We also predicted a gradual increase Km values with increasing temperature. The kinetic parameters six enzymes involved cycles C, (cellobiohydrolase, β-glucosidase and xylanase), P (phosphatase), N (leucine-aminopeptidase, tyrosine-aminopeptidase) were determined after one month incubation range 0–40 °C (with 5° increment). Contrary our hypothesis, was not for most enzymes. Within large temperatures from 0 15 °C 0–20 °C (enzymes cycle) (proteases) hydrolytic activity governed by nearly constant affinity. Temperature, therefore, mainly selected systems maintaining static Km. catalytic efficiency (Vmax/Km) increased low intermediate (0–20 °C) as result linear Vmax Static explained either flexibility (high structural stability) single type, which catalyzed reaction over broad range, or production multiple isoenzymes each different optima but similar substrate. Thus, ensured high within range.