Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Pivot Concepts:
Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Target Concepts:
Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Query: EC:3.4.21.4 (
trypsin
)
42,187
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
De novo purine biosynthesis is localized to both mitochondria and plastids isolated from Bradyrhizobium sp.-infected cells of cowpea (Vigna unguiculata L. Walp) nodules, but several of the pathway enzymes, including aminoimidazole ribonucleotide synthetase (
AIRS
[EC 6.3.3.1], encoded by Vupur5), are encoded by single genes. Immunolocalization confirmed the presence of
AIRS
protein in both organelles. Enzymatically active
AIRS
was purified separately from nodule mitochondria and plastids. N-terminal sequencing showed that these two isoforms matched the Vupur5 cDNA sequence but were processed at different sites following import; the mitochondrial isoform was five amino acids longer than the plastid isoform. Electrospray tandem mass spectrometry of a
trypsin
digest of mitochondrial
AIRS
identified two internal peptides identical with the amino acid sequence deduced from Vupur5 cDNA. Western blots of proteins from mitochondria and plastids isolated from root tips showed a single
AIRS
protein present at low levels in both organelles. (35)S-
AIRS
protein translated from a Vupur5 cDNA was imported into isolated pea (Pisum sativum) leaf chloroplasts in vitro by an ATP-dependent process but not into import-competent mitochondria from several plant and non-plant sources. Components of the mature protein are likely to be important for import because the N-terminal targeting sequence was unable to target green fluorescent protein to either chloroplasts or mitochondria in Arabidopsis leaves. The data confirm localization of the protein translated from the
AIRS
gene in cowpea to both plastids and mitochondria and that it is cotargeted to both organelles, but the mechanism underlying import into mitochondria has features that are yet to be identified.
...
PMID:Dual intracellular localization and targeting of aminoimidazole ribonucleotide synthetase in cowpea. 1264 56
