RGD Reference Report - Essential arginine residues in isoprenylcysteine protein carboxyl methyltransferase. - Rat Genome Database

Send us a Message



Submit Data |  Help |  Video Tutorials |  News |  Publications |  Download |  REST API |  Citing RGD |  Contact   

Essential arginine residues in isoprenylcysteine protein carboxyl methyltransferase.

Authors: Boivin, D  Lin, W  Beliveau, R 
Citation: Boivin D, etal., Biochem Cell Biol. 1997;75(1):63-9.
RGD ID: 2289655
Pubmed: PMID:9192075   (View Abstract at PubMed)

We used specific amino acid modifying reagents to characterize the isoprenylcysteine carboxyl methyltransferase in kidney membranes. The enzyme was inactivated by reagents specific for arginine, histidine, cysteine, and tryptophan residues. Protection by the product and inhibitor S-adenosyl-L-homocysteine was observed for arginine modification by phenylglyoxal and tryptophan modification by N-bromosuccinimide. We focused on modification by phenylglyoxal, a highly specific modifier of arginine residues. The inactivation of methyltransferase by phenylglyoxal follows pseudo-first-order kinetics and the order of the reaction, n, with respect to phenylglyoxal was 1.2. The inactivation increased with the alkalinity of the preincubation medium and was maximal at pH 10. Kinetic analysis showed that the K(m) for S-adenosyl-L-methionine is not significantly affected by treatment with phenylglyoxal but that the Vmax is reduced p-Hydroxyphenylglyoxal, a more hydrophilic derivative of phenylglyoxal, was a less potent inactivator of methyltransferase than phenylglyoxal, suggesting that arginine residues modified are in a hydrophobic environment. The methyltransferase is protected from phenylglyoxal modification by S-adenosyl-L-homocysteine but not S-adenosyl-L-methionine, sinefungin, N-acetyl-S-farnesyl-L-cysteine, or farnesylthioacetate. The arginine residue modified may thus be located either at the active site or at another additional binding site for S-adenosyl-L-homocysteine. These results indicate that arginine residues are essential for the enzymatic activity of isoprenylcysteine carboxyl methyltransferase.



Gene Ontology Annotations    Click to see Annotation Detail View

Biological Process

  
Object SymbolSpeciesTermQualifierEvidenceWithNotesSourceOriginal Reference(s)
IcmtRatC-terminal protein methylation  IMP  RGD 
IcmtRatS-adenosylhomocysteine metabolic process  IMP  RGD 
IcmtRatS-adenosylmethioninamine metabolic process  IMP  RGD 

Molecular Function

  
Object SymbolSpeciesTermQualifierEvidenceWithNotesSourceOriginal Reference(s)
IcmtRatprotein C-terminal S-isoprenylcysteine carboxyl O-methyltransferase activity  IMP  RGD 

Objects Annotated

Genes (Rattus norvegicus)
Icmt  (isoprenylcysteine carboxyl methyltransferase)


Additional Information