Patents by Inventor Xian X. Du

Xian X. Du 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).

  • Coding sequence for protein phosphatase methylesterase, recombinant DNA molecules and methods
    Publication number: 20030186416
    Abstract: Carboxymethylation of proteins is a highly conserved means of regulation in eukaryotic cells. The protein phosphatase 2A (PP2A) catalytic (C) subunit is reversibly methylated at its carboxy-terminus by specific methylesterase. Carboxymethylation affects PP2A activity and varies during the cell cycle. The present disclosure provides the coding sequence of a methylesterase, herein named Protein Phosphatase Methylesterase-1 (PME-1). PME-1 is highly conserved from yeast to human and contains a motif found in lipases, which motif has a catalytic triad-activated serine as the active site nucleophile. Recombinant PME-1 polypeptide produced in bacteria demethylates PP2A C subunit in vitro and okadaic acid, a known inhibitor of the PP2A methylesterase, inhibited this reaction. PME-1 represents the first mammalian protein phosphatase methylesterase cloned to date.
    Type: Application
    Filed: January 29, 2003
    Publication date: October 2, 2003
    Inventors: David C. Pallas, Xian X. Du
  • Protein phosphatase methylesterase
    Patent number: 6528295
    Abstract: Carboxymethylation of proteins is a highly conserved means of regulation in eukaryotic cells. The protein phosphatase 2A (PP2A) catalytic (C) subunit is reversibly methylated at its carboxy-terminus by specific methylesterase. Carboxymethylation affects PP2A activity and varies during the cell cycle. The present disclosure provides the coding sequence of a methylesterase, herein named Protein Phosphatase Methylesterase-1 (PME-1). PME-1 is highly conserved from yeast to human and contains a motif found in lipases, which motif has a catalytic triad-activated serine as the active site nucleophile. Recombinant PME-1 polypeptide produced in bacteria demethylates PP2A C subunit in vitro and okadaic acid, a known inhibitor of the PP2A methylesterase, inhibited this reaction. PME-1 represents the first mammalian protein phosphatase methylesterase cloned to date.
    Type: Grant
    Filed: April 20, 2001
    Date of Patent: March 4, 2003
    Assignee: Emory University
    Inventors: David C. Pallas, Xian X. Du
  • Coding sequence for protein phosphatase methylesterase, recombinant DNA molecules and methods
    Publication number: 20020107374
    Abstract: Carboxymethylation of proteins is a highly conserved means of regulation in eukaryotic cells. The protein phosphatase 2A (PP2A) catalytic (C) subunit is reversibly methylated at its carboxy-terminus by specific methylesterase. Carboxymethylation affects PP2A activity and varies during the cell cycle. The present disclosure provides the coding sequence of a methylesterase, herein named Protein Phosphatase Methylesterase-1 (PME-1). PME-1 is highly conserved from yeast to human and contains a motif found in lipases, which motif has a catalytic triad-activated serine as the active site nucleophile. Recombinant PME-1 polypeptide produced in bacteria demethylates PP2A C subunit in vitro and okadaic acid, a known inhibitor of the PP2A methylesterase, inhibited this reaction. PME-1 represents the first mammalian protein phosphatase methylesterase cloned to date.
    Type: Application
    Filed: April 20, 2001
    Publication date: August 8, 2002
    Inventors: David C. Pallas, Xian X. Du