• Heme, Not Just the Red Pigment in Blood.

    Heme, an iron-containing porphyrin, functions as a prosthetic group in numerous proteins. These range from components of the electron transport chain to many enzymes. No wonder the biosynthesis of heme is highly conserved in evolution!

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    Blood Cells

    put in the public domain by NCI/Donald BlissBruce Wetzel and Harry Schaefer.

  • Navigate Metabolic Map for Pathways

    The Cellular Overview enables you to browse through a zoomable metabolic map diagram that displays pathways according to groups based on biological function, or classes of metabolites produced/consumed.

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    Cellular Overview

    Cellular overview image generated by Pathway Tools

  • Important Mammalian Pathways: The Urea Cycle

    The urea cycle is responsible for mediating excretion of nitrogenous waste. It was the first metabolic pathway to be discovered, five years before the discovery of the TCA cycle. The cycle occurs across both the cytosol and the mitchondrion.

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    Mitochondria, mammalian lung - TEM

    colorized selection from Mitochondria, mammalian lung - TEMput in the Public Domain by author, Louisa Howard.

  • RouteSearch: Search for Paths through the Metabolic Network

    Search for lowest-cost paths through the metabolic network of the selected organism. Or, design lowest-cost pathways to novel compounds by adding reactions from MetaCyc.

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    Route Search Diagram


  • A Pathway Linked to Central Nervous System Disorders

    The GABA shunt forms a closed loop in the CNS for conserving the supply of the excitatory neurotransmitter GABA. One of the enzymes of this pathway, 4-aminobutyrate aminotransferase is a target for the anti-epileptic drug vigabatrin.

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    Brain MRI

    selection from Brain MRI Source: Dr. Leon Kaufman. UCSF.

  • Metabolomics Data Analysis

    Multiple tools are available in this website for metabolomics data analysis.

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    Enrichment dialog displayed over SmartTable

    SmartTable display generated by Pathway Tools.

  • The Truth about the Thanksgiving Turkey...

    Of the 20 amino acids, at least 9 are essential. Essential L-tryptophan is required for serotonin, melatonin and niacin synthesis. Its requirement for NAD biosynthesis was discovered when humans stricken with pellagra recovered after the addition of tryptophan or niacin to their diets.

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  • Gene Expression Data Analysis

    Multiple tools are available in this website for analysis of gene expression data.

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    WebOmics Image

    Cellular Overview Omics Viewer image generated by Pathway Tools.

HumanCyc: Encyclopedia of Human Genes and Metabolism

HumanCyc provides an encyclopedic reference on human metabolic pathways, the human genome, and human metabolites.

HumanCyc is part of the larger BioCyc collection of thousands of Pathway/Genome Databases for sequenced genomes. Click the "Change Current Database" button above to explore the available databases.

For more information on HumanCyc, see our article "Computational prediction of human metabolic pathways from the complete human genome" in Genome Biology.

User Guide

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Learning Library

Webinar Series

Webinar #1: Introduction to BioCyc
These six sequential segments, giving you a guided tour of the BioCyc collection in concise bites. To download or view, just click on one of the links following each segment's name.
Webinar #2: Introduction to SmartTables
The following webinar will guide you through SmartTables, which enable you to create, upload, share, and analyze sets of genes, metabolites, pathways, and sequence sites. The webinar is broken up into parts, ranging from basic operations to more advanced uses such as gene expression analysis and metabolomics. To download or view, click one of the links below.
Webinar #3: Zoomable Metabolic Map, Comparative Tools, Regulatory Network
This webinar introduces users to many of the advanced tools available on the BioCyc.org website for navigating cellular networks, analyzing large-scale datasets, and comparing organisms.
Webinar #4: Omics Data Analysis
This webinar will show you how to use BioCyc's tools for omics data analysis, including the cellular omics viewer, the omics dashboard, and other tools.
Webinar #5: Pathway Collages
Pathway collages are multi-pathway diagrams that you can customize by, for example, overlaying omics data, altering the relative positions of pathways, and modifying connections among pathways. Learn how to generate, customize and export high-quality pathway-collage diagrams showing collections of user-specified pathways.
Webinar #6: Creating a Pathway/Genome Database
Learn the entire process of building a BioCyc-like Pathway/Genome Database (PGDB) for an organism with a sequenced and annotated genome. Build a PGDB for your own lab or for the whole scientific community.
Webinar #7: Using the Structured Advanced Query Page
An introduction to the Structured Advanced Query Page, which allows complex queries and queries across one or more databases in the BioCyc collection. You'll learn about:The basic steps of setting up an advanced query; Four examples of increasingly complex queries, including how to query across multiple databases; Where to learn more about the structure of BioCyc databases.