Related Experiment Video
Updated: Jul 19, 2026

The Organoid Reconstitution Assay (ORA) for the Functional Analysis of Intestinal Stem and Niche Cells
Published on: November 20, 2017
ORENZA: a web resource for studying ORphan ENZyme activities.
Olivier Lespinet1, Bernard Labedan
1Institut de Génétique et Microbiologie, CNRS UMR 8621, Université Paris-Sud, Bâtiment 400, 91405 Orsay Cedex, France. olivier.lespinet@igmors.u-psud.fr
A new database, ORENZA, addresses the significant gap between known enzyme functions and their corresponding genetic sequences. This resource aims to link sequence-less enzyme activities (EC numbers) with genomic data, aiding researchers.
Area of Science:
- Biochemistry
- Bioinformatics
- Genomics
Background:
- Over 36% of defined enzyme activities lack associated amino acid sequences in public databases.
- This gap exists across nearly all enzyme classes, hindering research.
- There is a critical need to identify sequences for these 'orphan' enzyme activities.
Purpose of the Study:
- To introduce ORENZA, a database for collating information on enzyme activities (EC numbers).
- To specifically focus on and facilitate the study of orphan enzyme activities.
- To bridge the gap between enzyme function and sequence data.
Main Methods:
- Developed ORENZA, a PostgreSQL database for enzyme activity information.
- Included comprehensive lists of all EC numbers and orphan EC numbers, with periodic updates.
- Enabled searching by EC number, enzyme name, species, biochemical properties, and metabolic pathways.
Main Results:
- ORENZA clearly indicates the association between enzyme activities and amino acid sequences.
- Identifies orphan enzyme activities, making them readily discoverable.
- Provides a platform for community-driven suggestions for re-annotating orphan EC numbers.
Conclusions:
- ORENZA is a web resource designed to reduce the number of unassigned enzyme activities.
- It aims to foster collaboration between biochemists and genomicists.
- Facilitates the allocation of gene sequences to their corresponding enzymes, thereby closing the function-sequence gap.
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