Hydroxylation of aspartic acid in domains homologous to the epidermal growth factor precursor is catalyzed by a 2-oxoglutarate-dependent dioxygenase.
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.
Stenflo
J
J
Department of Clinical Chemistry, University of Lund, Malmö General Hospital, Sweden.
Holme
E
E
Lindstedt
S
S
Chandramouli
N
N
Huang
L H
LH
Tam
J P
JP
Merrifield
R B
RB
D000595:Amino Acid Sequence; D000818:Animals; D001224:Aspartic Acid / Q000378:metabolism*; D002245:Carbon Dioxide / Q000378:metabolism; D004815:Epidermal Growth Factor / Q000378:metabolism*; D005164:Factor IX / Q000378:metabolism; D006801:Humans; D006900:Hydroxylation; D007656:Ketoglutaric Acids / Q000378:metabolism; D008862:Microsomes, Liver / Q000201:enzymology; D006899:Mixed Function Oxygenases / Q000378:metabolism*; D008969:Molecular Sequence Data; D011487:Protein Conformation; D011498:Protein Precursors / Q000378:metabolism*; D051381:Rats
D007656:Ketoglutaric Acids; D011498:Protein Precursors; C042652:epidermal growth factor precursor; D002245:Carbon Dioxide; D001224:Aspartic Acid; D004815:Epidermal Growth Factor; D005164:Factor IX; D006899:Mixed Function Oxygenases; C058291:aspartic acid 2-oxoglutarate-dependent dioxygenase