Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.3.1.109 (AST)
 6,066 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The cDNA encoding the precursor polypeptide for schistostatins, allatostatin-like peptides which have been shown to inhibit peristaltic movements of the lateral oviducts of Schistocerca gregaria, has been cloned and sequenced. Translation of this sequence reveals the presence of a pre-proschistostatin consisting of 283 amino acids. It contains ten different peptide sequences which are flanked by dibasic cleavage sites and C-terminal amidation signals. Eight of these peptides were identical to the schistostatins (or Scg-ASTs) that were previously purified from Schistocerca gregaria brain extracts. Two novel peptide sequences were discovered. One of these is the first AST-like peptide which has a C-terminal valine residue. Two peptides contain within their sequence an internal dibasic site which suggests a possible role for alternative processing and/or degradation. The schistostatin precursor differs from cockroach pre-proallatostatins in size, in sequence and in organization. It contains a lower number of peptides (10 versus 13 or 14) which are interrupted only once by an acidic spacer region (versus four in Diploptera punctata and Periplaneta americana). Northern analysis showed the presence of a 2.4 kb mRNA band in the locust central nervous system and midgut. This indicates that schistostatins, like other ASTs, are a good example of insect brain/gut peptides.
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PMID:Molecular cloning of the precursor cDNA for schistostatins, locust allatostatin-like peptides with myoinhibiting properties. 890 49

The genome region encoding the RNA-dependent RNA polymerase 3CD-like precursor from rabbit hemorrhagic disease virus (RHDV) (isolate AST/89) was cloned and expressed in Escherichia coli using polyhistidine fusion-based vectors. The full-length recombinant 3CD-like precursor polypeptide could not be purified as a consequence of its autoproteolytic processing. A Cys-->Gly substitution of the 3C-like catalytic cysteine (C1212) impeded the cleavage and allowed the purification of the precursor at high yields using a polyhistidine fusion expression vector. Equimolar amounts of purified recombinant precursor (C1212G mutant) and mature 3D-like polymerase showed significant activity differences in genome-linked protein (VPg) uridylylation and RNA polymerization using in vitro assays. The data indicated that the precursor was more active than the mature polymerase in catalysing RHDV VPg uridylylation, whereas the latter enzyme form had higher activity than its precursor in RNA polymerization in vitro assays using a heteropolymeric RNA template.
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PMID:Functional differences between precursor and mature forms of the RNA-dependent RNA polymerase from rabbit hemorrhagic disease virus. 1943 53