Aldolase (E.C. from the flight muscle of the locust, Schistocerca americana gregaria, was purified to homogeneity using phosphocellulose affinity chromatography. The activity of the enzyme (13 units/g wet wt.) was one of the lowest of the glycolytic enzymes in flight muscle. The enzyme has a molecular weight of 155,000 ± 5000, a pI of 4.9 ± 0.5, a pH optimum of 7.3 in Tris buffer, and a Km for fructose-1.6-P2 of 4.0 ± 0.5 μM. The enzyme resembles muscle aldolases from other sources in displaying a Vmax activity ratio ( Vfructose-1,6-P2 Vfructose-1-P) of 37. The enzyme was inhibited by the adenylates (ATP, ADP, AMP), NAD+, NADH, excess Mg2+ and Mn2+, citrate, and palmitoyl-carnitine. Only citrate (Ki = 1.88 ± 0.20 mM) and palmitoyl-carnitine (Ki = 18 ± 4 μM) appear to be significant effectors of the enzyme in vivo. Inhibition by these two compounds was mixed competitive with respect to fructose-1,6-P2. Citrate and palmitoyl-carnitine inhibitions of aldolase may be the signals used to inhibit flight muscle glycolysis during lipid oxidation. The central role of aldolase in the transition from short-term, carbohydrate based flight to long-term, lipid-based flight in the locust is discussed.

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Insect Biochemistry
Department of Biology

Storey, K. (1980). Kinetic properties of purified aldolase from flight muscle of Schistocerca americana gregaria. Role of the enzyme in the transition from carbohydrate to lipid-fueled flight. Insect Biochemistry, 10(6), 647–655. doi:10.1016/0020-1790(80)90054-2