Table 9 Example artifactual orphans
EC No. | Enzyme Name | Original Species | Year | Swiss-Prot/TrEMBL Acc. No. | Cause of artifact | Significance of error; importance of orphan activity |
|---|---|---|---|---|---|---|
3.4.21.103 | Physarolisin (a proteinase) | Physarum flavicomum | 1982 | Q8MZS4 | IUBMB entry lists a 2003 paper describing a gene coding for a protein with this activity [28]. Sequence is in Swiss-Prot but ENZYME does not reference this sequence. | Lack of database cross-referencing presumably involving the long interval between the initial characterization of the activity and the cloning of the gene. |
3.5.2.16 | Maleimide hydrolase | Blastobacter sp. A17p-4 | 1997 | Q93T25 | ENZYME and IUBMB entries are not referencing a Swiss-Prot entry from a 2002 paper describing the cloning of gene coding for this [29]. | Lack of database cross-referencing is not restricted to older orphans. |
3.5.1.79 | Phthalyl amidase | Xanthobacter agilis | 1995 | N/A | The sequence, listed in a patent associated with a 1996 paper by [30] in Journal of Molecular Catalysis B: Enzymatic are available from Entrez, but not from TrEMBL. The paper itself is not available from PubMed. | Note: though the protein sequence is not available from the UniProt database, the DNA sequence is present in the EMBL database. |
3.1.8.2 | Diisopropyl-fluoro-phosphatase | Alteromonas sp. | 1954 | Q44238 | ENZYME and IUBMB entries are not referencing a Swiss-Prot entry associated with a 1996 paper describing the cloning of a gene coding for an enzyme with this activity [31]. | This enzymatic activity detoxifies nerve gas. The gene is part of a widespread gene family with otherwise unknown function, with members in Homo sapiens. |