Rhea Download

What is Rhea Download?

Rhea Download is a record-retrieval tool for Rhea, an expert-curated knowledgebase of biochemical and transport reactions of biological interest. It retrieves the RDF representation of one reaction identified by its Rhea accession, such as RHEA:10000. Rhea uses ChEBI chemical entities to describe reaction participants and provides curated links to enzyme classifications and other biological resources where available.

The tool answers a specific lookup question: “What is the machine-readable Rhea record for this known reaction?” It does not infer a reaction from a protein sequence, search a pathway, or assign an EC number. That distinction matters when preserving the reaction definition behind an enzyme annotation, a metabolic-model entry, or a cross-reference in a report.

Rhea reactions are especially useful as stable, curated identifiers for chemistry that is linked to protein annotation. A reaction can have associated EC numbers, but an EC number and a Rhea ID are not interchangeable: the Rhea record represents a reaction definition, while EC classification groups enzyme-catalyzed reactions.

How to use Rhea Download online

ProteinIQ retrieves a single Rhea reaction online from its accession and returns the corresponding RDF/XML record as a downloadable file. Enter a Rhea ID such as RHEA:10000 or 10000, fetch the record, then retain the RDF alongside pathway data, enzyme annotations, or software outputs that need a precise reaction identifier.

Input

Input	Description
Entry ID	One Rhea reaction identifier. RHEA:10000, RHEA:10164, and RHEA:12345 are accepted examples. The RHEA: prefix is optional.

The input identifies an existing Rhea reaction, not a protein accession, enzyme name, EC number, ChEBI identifier, or free-text reaction query. When only a compound, enzyme, EC number, or reaction description is known, locate the matching Rhea reaction in Rhea first, then use its RHEA: accession here.

Settings

Setting	Description
Database	Defaults to Rhea. Selecting a different database changes the retrieval source and requires an identifier valid for that source. Keep Rhea selected for Rhea accessions.

Output

Output	Format	Contents
Rhea reaction record	RDF/XML (.xml)	The RDF representation of the requested Rhea reaction.
Result details	Metadata	Database, Rhea ID, reaction title, record type, file label, filename, format, source URL, and available reaction equation and EC-number information.

The Files panel provides the RDF/XML document for download. ProteinIQ uses an identifier-based filename, for example rhea-10000-rdf.xml, so the file can be retained with analyses without relying on a reaction name or equation as a file label.

Understanding the reaction record

RDF, the Resource Description Framework, represents data as linked statements. Rhea publishes this form so reaction definitions and their identifiers can be read by software or queried alongside other RDF data. The downloaded file is therefore most useful for structured data integration, provenance capture, and semantic-web workflows rather than as a human-friendly reaction report.

The result details give a quick view of the fields fetched for the record:

Field	Meaning
Rhea ID	The normalized numeric Rhea identifier, corresponding to the submitted RHEA: accession.
Equation	The curated chemical equation returned for the reaction. It describes the reaction, not measured flux, rate, equilibrium, or enzyme activity in a particular organism.
EC numbers	Linked Enzyme Commission classifications when Rhea supplies them. A missing value does not establish that the reaction is non-enzymatic or biologically irrelevant.
RDF	The downloadable RDF/XML representation of the reaction record.

Rhea uses ChEBI entities for reaction participants. A participant identifier points to a defined chemical entity, which is more reliable for automated analysis than matching compounds only by a display name. To retain chemical-entity metadata together with a reaction workflow, ChEBI Download retrieves a ChEBI record by accession.

Where Rhea Download fits in an annotation workflow

Rhea Download is most useful after another resource has already produced a Rhea ID. For example, a UniProt enzyme annotation may carry a Rhea cross-reference, or a pathway table may identify reactions with Rhea accessions. Fetching the individual RDF records at that point preserves the versioned, machine-readable definitions used to interpret those identifiers.

• Store the Rhea RDF file with a metabolic-model export or supplementary dataset to preserve the exact reaction reference.
• Use the equation and linked EC-number metadata to check that an annotation table points to the intended chemistry.
• Parse RDF identifiers and links in a graph database or RDF-aware workflow rather than extracting meaning from a file name.
• Pair reaction records with UniProt protein records when both the annotated protein and the catalyzed reaction need to be retained.

This tool retrieves one known record per run. It does not provide batch mapping, full-text discovery, reaction similarity search, pathway reconstruction, kinetic parameters, or protein-specific evidence that an enzyme catalyzes the downloaded reaction. Those questions require the appropriate Rhea search or mapping workflow and, for a particular protein, the relevant sequence and annotation evidence.

Rhea content changes with database releases. The RDF file is a retrieval-time snapshot, so analyses that depend on exact reaction definitions should retain the Rhea accession, download date, and the retrieved file alongside the study or pipeline output.