Patents by Inventor Howard Zalkin

Howard Zalkin 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).

  • Deregulation of glutamine PRPP amidotransferase activity
    Publication number: 20030166166
    Abstract: The present invention is directed methods of purine synthesis using a modified amidotransferase, wherein the modified glutamine PRPP amidotransferase has reduced sensitivity to end-product inhibition of synthesizing purine nucleotides.
    Type: Application
    Filed: April 3, 2003
    Publication date: September 4, 2003
    Inventors: Howard Zalkin, Janet L. Smith, Robert L. Switzer
  • Deregulation of glutamine PRPP amidotransferase activity
    Patent number: 6586216
    Abstract: The present invention is directed to a modified amidotransferase. The amino acid sequence of the modified amidotransferase differs from the amino acid sequence of a native E. coli glutamine PRPP amidotransferase in that one or more amino acid residues of the modified amidotransferase are substituted at positions equivalent to amino acid positions in Bacillus amidotransferase selected from the group consisting of 282, 283, 307, and 347 of SEQ ID NO:1, wherein the modified amidotransferase is less sensitive to end-product inhibition than is the native E. coli glutamine PRPP amidotransferase.
    Type: Grant
    Filed: March 13, 2001
    Date of Patent: July 1, 2003
    Assignees: Purdue Research Foundation, The Board of Trustees of the University of Illinois
    Inventors: Howard Zalkin, Janet L. Smith, Robert L. Switzer
  • Deregulation of glutamine PRPP amidotransferase activity
    Publication number: 20010031486
    Abstract: The present invention is directed to a modified glutamine PRPP amidotransferase and a method of using that modified enzyme to enhance the biosynthesis of purine nucleotides. The modified glutamine PRPP amidotransferase has at least one amino acid of the allosteric A sites or the catalytic C sites of said amidotransferase substituted with a non-native amino acid, wherein the substitution reduces the sensitivity of the enzyme to end product inhibition relative to the native glutamine PRPP amidotransferase enzyme.
    Type: Application
    Filed: March 13, 2001
    Publication date: October 18, 2001
    Inventors: Howard Zalkin, Janet L. Smith, Robert L. Switzer
  • Deregulation of glutamine PRPP amidotransferase activity
    Patent number: 6204041
    Abstract: The present invention is directed to a modified glutamine PRPP amidotransferase and a method of using that modified enzyme to enhance the biosynthesis of purine nucleotides. The modified glutamine PRPP amidotransferase has at least one amino acid of the allosteric A sites or the catalytic C sites of said amidotransferase substituted with a non-native amino acid, wherein the substitution reduces the sensitivity of the enzyme to end product inhibition relative to the native glutamine PRPP amidotransferase enzyme.
    Type: Grant
    Filed: September 9, 1998
    Date of Patent: March 20, 2001
    Assignees: The Board of Trustees of the University of Illinois, Purdue Research Foundation
    Inventors: Howard Zalkin, Janet Louise Smith, Robert Lee Switzer