Patents by Inventor Walther Johannssen

Walther Johannssen has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Nitrate reductase from yeasts, the preparation and use thereof
    Patent number: 5294539
    Abstract: The invention relates to NAD(P)H-dependent nitrate reductase from yeasts, to a process for the preparation thereof and to the use thereof in a reagent for determining nitrate. The nitrate reductase is characterized by a molecular weight of about 350 000 D and can be obtained by yeast cells which have been cultivated in a completely synthetic nutrient medium with nitrate as the sole nitrogen source and which contain nitrate reductase being disrupted in phosphate buffer, the crude extract being chromatographed on an anion exchanger, the fractions containing nitrate reductase being mixed with protein, concentrated by ultrafiltration and dried by fluidized bed granulation. The reagent for determining nitrate contains, besides the nitrate reductase prepared in this way, also NAD(P)H and a color reagent for determining nitrite.
    Type: Grant
    Filed: October 16, 1991
    Date of Patent: March 15, 1994
    Assignee: Merck Patent Gesellschaft mit beschrankter Haftung
    Inventors: Walther Johannssen, Harry Schwartz, Reiner Gromes, Martin Heinrich