Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.30.1 (S1 nuclease)
 3,660 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

cDNA clones of the mRNA for bovine adrenal cytochrome P-450(11 beta) were isolated. Sequence analysis of a 4 kb long cDNA revealed the primary structure of P-450(11 beta), which consisted of 503 amino acids (Mr: 57,924) and contained an extension peptide of 24 amino acids at the NH2-terminus of the mature P-450(11 beta). molecule. A bovine genomic DNA containing the 1st exon and its leader sequence of P-450(11 beta) gene was also isolated from a bovine gene library. Determination of the transcription initiation site by S1 nuclease analysis using the cloned genomic DNA confirmed that the methionine codon near the 5' side of the 4 kb long cDNA was the initiation codon. Comparisons of the primary structures among P-450(11 beta) and other forms of cytochrome P-450 including P-450(SCC) indicated that the two mitochondrial P-450s, P-450(11 beta) and P-450(SCC), were significantly different from microsomal forms of cytochrome P-450. The homology between P-450(11 beta) and P-450(SCC) was 36%, which is higher than the values between P-450(11 beta) and various microsomal P-450s. An alignment of P-450(11 beta) and P-450(SCC) to give maximum matching showed four highly conserved regions (C-1, C-2, C-3, and C-4). The homology values of these regions were 58-70%, considerably higher than the overall homology between these two mitochondrial P-450s. A putative heme binding site and a steroid binding site were located in the conserved regions. Hydropathy profiles of P-450(11 beta) and P-450(SCC) were very similar. A definite difference was noticed at the NH2-terminal portion between mitochondrial and microsomal types of P-450. Microsomal type of cytochrome P-450 had a hydrophobic sequence consisting of about 20 amino acids, whereas mitochondrial type had an extension peptide containing many positively changed amino acids.
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PMID:Molecular cloning and nucleotide sequence of DNA of mitochondrial cytochrome P-450(11 beta) of bovine adrenal cortex. 342 48

Histidase (EC 4.3.1.3) is a cytosolic enzyme that catalyzes the nonoxidative deamination of histidine to urocanic acid. Histidinemia, resulting from reduced histidase activity as reported in Cambridge stock his/his mice and in humans, is the most frequent inborn metabolic error in Japan. The histidase chromosomal gene (HAL) was isolated from a lambda EMBL-3 human genomic library using the human histidase cDNA as a probe. Restriction mapping and Southern blot analysis of the isolated clones reveal a single-copy gene spanning approximately 25 kb and consisting of 21 exons. Exon 1 encodes only 5' untranslated sequence of liver histidase mRNA, with protein coding beginning in exon 2. A rarely observed 5' GC, similar to that reported in the human P-450 (SCC) gene, is present in intron 20. All other splicing junctions adhere to the canonical GT/AG rule. A TATA box sequence is located 25 bp upstream of the liver histidase transcription initiation site determined by S1 nuclease protection analysis. Several liver- and epidermis-specific transcription factor binding sites, including C/EBP, NFIL6, HNF5, AP2/KER1, MNF, and others, are also identified in the 5' flanking region. Consistent with the hepatic and epidermal expression of histidase, this finding suggests that histidase transcription may be regulated by these factors. We further identify a polymorphism (A to G transition) in the histidase coding region of exon 16. The human histidase genomic structure presented here should facilitate the molecular investigation of symptomatic and asymptomatic forms of histidinemia.
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PMID:Molecular cloning and structural characterization of the human histidase gene (HAL). 853 Jan 7