Open AccessHydroxylation of aspartic acid in domains homologous to the epidermal growth factor precursor is catalyzed by a 2-oxoglutarate-dependent dioxygenase.
Author(s) -
Johan Stenflo,
Elisabeth Holme,
Sven Lindstedt,
Nagarajan Chandramouli,
Linda H. Huang,
James P. Tam,
R. B. Merrifield
Publication year - 1989
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.86.2.444
Subject(s) - aspartic acid , dioxygenase , hydroxylation , asparagine , epidermal growth factor , biochemistry , decarboxylation , chemistry , amino acid , enzyme , biology , stereochemistry , catalysis , receptor
3-Hydroxyaspartic acid and 3-hydroxyasparagine are two rare amino acids that are present in domains homologous to the epidermal growth factor precursor in vitamin K-dependent plasma proteins as well as in proteins that do not require vitamin K for normal biosynthesis. They are formed by posttranslational hydroxylation of aspartic acid and asparagine, respectively. The first epidermal growth factor-like domain in factor IX (residues 45-87) was synthesized with aspartic acid in position 64, replacing 3-hydroxyaspartic acid. It was used as substrate in a hydroxylase assay with rat liver microsomes as the source of enzyme and reaction conditions that satisfy the requirements of 2-oxoglutarate-dependent dioxygenases. The synthetic peptide stimulated the 2-oxoglutarate decarboxylation in contrast to synthetic, modified epidermal growth factor (Met-21 and His-22 deleted and Glu-24 replaced by Asp) and synthetic peptides corresponding to residues 60-71 in human factor IX. This indicates that the hydroxylase is a 2-oxoglutarate-dependent dioxygenase with a selective substrate requirement.