Bibliographic Citation
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| Title | Mutations affecting enzymatic activity in liver arginase |
| Creator/Author | Vockley, J.G. ; Tabor, D.E. ; Goodman, B.K. [UCLA School of Medicine, Los Angeles, CA (United States)] [and others] |
| Publication Date | 1994 Sep 01 |
| OSTI Identifier | OSTI ID: 133978 |
| Report Number(s) | CONF-941009-- |
| Other Number(s) | Journal ID: AJHGAG; ISSN 0002-9297; TRN: TRN: 95:005313-0713 |
| Resource Type | Journal Article |
| Resource Relation | Journal Name: American Journal of Human Genetics; Journal Volume: 55; Journal Issue: Suppl.3; Conference: 44. annual meeting of the American Society of Human Genetics, Montreal (Canada), 18-22 Oct 1994; Other Information: PBD: Sep 1994 |
| Subject | 55 BIOLOGY AND MEDICINE, BASIC STUDIES; GENES; GENE MUTATIONS; MUTAGENESIS; ENZYME ACTIVITY; GENETIC EFFECTS; ARGINASE; PATIENTS; METABOLIC DISEASES; POLYMERASE CHAIN REACTION; NUCLEOTIDES |
| Description/Abstract | The hydrolysis of arginine to ornithine and urea is catalyzed by arginase in the last step of the urea cycle. We examined a group of arginase deficient patients by PCR-SSCP analysis to characterize the molecular basis of this disorder. A heterogeneous population of nonsense mutations, microdeletions, and missense mutations has been identified in our cohort. Microdeletions which introduce premature stop codons downstream of the deletion and nonsense mutations result in no arginase activity. These mutations occur randomly along the gene. The majority of missense mutations identified appear to occur in regions of high cross-species homology. To test the effect of these missense mutations on arginase activity, site-directed mutagenesis was used to re-create the patient mutations for in vivo expression studies in a prokaryotic fusion-protein expression system. Of 4 different missense mutations identified in 6 individuals, only one was located outside of a conserved region. The three substitution mutations within the conserved regions had a significant effect on enzymatic activity (0-3.1 nmole/30min, normal is 1300-1400 nmoles/30min, as determined by in vitro arginase assay), while the fourth mutation, a T to S substitution, did not. In addition, site-directed mutagenesis was utilized to create mutations not in residues postulated to play a significant role in the enzymatic function or active site formation in manganese-binding proteins such as arginase. We have determined that the substitution of glycine for a histidine residue, located in a very highly conserved region of exon 3, and the substitution of a histidine and an aspartic acid residue within a similarly conserved region in exon 4, totally abolishes enzymatic activity. Mutations substituting glycine for an additional histidine and aspartic acid residue in exon 4 and two aspartic acid residues in exon 7 have also been created. We are currently in the process of characterizing these mutations. |
| Country of Publication | United States |
| Language | English |
| Format | Medium: X; Size: pp. A178.1034 |
| System Entry Date | 2008 Feb 04 |
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Last Updated: 11/19/2009