Biomaterial Database

Posttranslational modification of glycine-extended substance P by an alpha-amidating enzyme in cultured sensory neurons of dorsal root ganglia. 1994

M Wong, and A Y Jeng

Research Department Ciba-Geigy Corp., Summit, New Jersey 07901.

The terminal step in the biosynthesis of substance P is the conversion of its glycine-extended precursor to the mature, amidated peptide by the alpha-amidating enzyme. This posttranslational modification was demonstrated in cultured, dissociated sensory neurons of dorsal root ganglia from neonatal rats. An assay was developed to quantitate both substance P and its precursor peptide in these cells. More than 90% of these two peptides was present as mature peptide in uncultured cells. In contrast, after 8 days in culture, about 85% of the peptides was the precursor, which increased 200-fold, whereas the level of substance P itself tripled during this culturing period. Since alpha-amidating enzyme requires ascorbate for activity, this reducing agent was added to the culture medium. Ascorbate induced a dose-dependent rise in the percentage of amidated peptide, with an apparent Km of 20 microM. After 5 days of culturing in the presence of 500 microM ascorbate, substance P increased 8-fold, constituting 70% of the total. The alpha-amidating enzyme also needs copper for activity. Even with 500 microM ascorbate in the culture medium, the copper chelator diethyldithiocarbamate dose-dependently reduced substance P synthesis by the sensory neurons, with a concomitant increase in its precursor peptide. These results suggest the presence of alpha-amidating enzyme in sensory neurons of dorsal root ganglia. It is likely that conversion of other glycine-extended precursors to their mature peptides in cell cultures would also require ascorbate and copper.

UI	MeSH Term	Description	Entries
D009097	Multienzyme Complexes	Systems of enzymes which function sequentially by catalyzing consecutive reactions linked by common metabolic intermediates. They may involve simply a transfer of water molecules or hydrogen atoms and may be associated with large supramolecular structures such as MITOCHONDRIA or RIBOSOMES.	Complexes, Multienzyme
D009419	Nerve Tissue Proteins		Proteins, Nerve Tissue,Tissue Proteins, Nerve
D009475	Neurons, Afferent	Neurons which conduct NERVE IMPULSES to the CENTRAL NERVOUS SYSTEM.	Afferent Neurons,Afferent Neuron,Neuron, Afferent
D011498	Protein Precursors		Precursors, Protein
D011499	Protein Processing, Post-Translational	Any of various enzymatically catalyzed post-translational modifications of PEPTIDES or PROTEINS in the cell of origin. These modifications include carboxylation; HYDROXYLATION; ACETYLATION; PHOSPHORYLATION; METHYLATION; GLYCOSYLATION; ubiquitination; oxidation; proteolysis; and crosslinking and result in changes in molecular weight and electrophoretic motility.	Amino Acid Modification, Post-Translational,Post-Translational Modification,Post-Translational Protein Modification,Posttranslational Modification,Protein Modification, Post-Translational,Amino Acid Modification, Posttranslational,Post-Translational Amino Acid Modification,Post-Translational Modifications,Post-Translational Protein Processing,Posttranslational Amino Acid Modification,Posttranslational Modifications,Posttranslational Protein Processing,Protein Processing, Post Translational,Protein Processing, Posttranslational,Amino Acid Modification, Post Translational,Modification, Post-Translational,Modification, Post-Translational Protein,Modification, Posttranslational,Modifications, Post-Translational,Modifications, Post-Translational Protein,Modifications, Posttranslational,Post Translational Amino Acid Modification,Post Translational Modification,Post Translational Modifications,Post Translational Protein Modification,Post Translational Protein Processing,Post-Translational Protein Modifications,Processing, Post-Translational Protein,Processing, Posttranslational Protein,Protein Modification, Post Translational,Protein Modifications, Post-Translational
D002478	Cells, Cultured	Cells propagated in vitro in special media conducive to their growth. Cultured cells are used to study developmental, morphologic, metabolic, physiologic, and genetic processes, among others.	Cultured Cells,Cell, Cultured,Cultured Cell
D002614	Chelating Agents	Chemicals that bind to and remove ions from solutions. Many chelating agents function through the formation of COORDINATION COMPLEXES with METALS.	Chelating Agent,Chelator,Complexons,Metal Antagonists,Chelators,Metal Chelating Agents,Agent, Chelating,Agents, Chelating,Agents, Metal Chelating,Antagonists, Metal,Chelating Agents, Metal
D003300	Copper	A heavy metal trace element with the atomic symbol Cu, atomic number 29, and atomic weight 63.55.	Copper-63,Copper 63
D004050	Ditiocarb	A chelating agent that has been used to mobilize toxic metals from the tissues of humans and experimental animals. It is the main metabolite of DISULFIRAM.	Diethyldithiocarbamate,Diethylcarbamodithioic Acid,Diethyldithiocarbamic Acid,Dithiocarb,Ditiocarb Sodium,Ditiocarb, Ammonium Salt,Ditiocarb, Bismuth Salt,Ditiocarb, Lead Salt,Ditiocarb, Potassium Salt,Ditiocarb, Sodium Salt,Ditiocarb, Sodium Salt, Trihydrate,Ditiocarb, Tin(4+) Salt,Ditiocarb, Zinc Salt,Imuthiol,Sodium Diethyldithiocarbamate,Thiocarb,Zinc Diethyldithiocarbamate,Ammonium Salt Ditiocarb,Bismuth Salt Ditiocarb,Diethyldithiocarbamate, Sodium,Diethyldithiocarbamate, Zinc,Lead Salt Ditiocarb,Potassium Salt Ditiocarb,Sodium Salt Ditiocarb,Sodium, Ditiocarb,Zinc Salt Ditiocarb
D005727	Ganglia, Spinal	Sensory ganglia located on the dorsal spinal roots within the vertebral column. The spinal ganglion cells are pseudounipolar. The single primary branch bifurcates sending a peripheral process to carry sensory information from the periphery and a central branch which relays that information to the spinal cord or brain.	Dorsal Root Ganglia,Spinal Ganglia,Dorsal Root Ganglion,Ganglion, Spinal,Ganglia, Dorsal Root,Ganglion, Dorsal Root,Spinal Ganglion