ATP- and polyphosphate-dependent bacterial NAD+ kinases

Measurable levels of activity of NAD⁺ kinases of actinomycetesMicrococcus luteus andCoryne-bacterium ammoniagenes were observed after substituting inorganic tripolyphosphate for ATP, whereas the enzyme from the eubacteriumEscherichia coli was not active with this substrate. Gradient PAGE found two molecular isoforms of NAD⁺ kinase inC. ammoniagenes andE. coli; four forms were found inM. luteus. All isoforms of this enzyme found inC. ammoniagenes andM. luteus displayed NADP-synthesizing activity in the presence of either ATP or tripolyphosphate. Because of its capability of utilizing inorganic tripolyphosphate,M. luteus is the most promising NADP producer organism.     

Characterization of Lipoxygenase from Fungi of the Genus Mortierella

The specific activity of lipoxygenase from several strains of the zygomycete Mortierellavaried from 1.02 to 2.02 mol diene per min per mg protein. The enzyme equally used linoleic or arachidonic acid as a substrate. An increase in lipoxygenase activity was observed after adding corn oil to the culture medium. Tests with inhibitors having different chemical structures revealed that the lipoxygenase activity from Mortierellacells was inhibited only by esculetin, ethanol, and nordihydroguaiaretic acid (NDGA). NDGA inhibited the enzyme in vitro(IC₅₀=142 M), but its addition in the exponential phase of growth activated the enzyme.