13198 IUPAC Gold Book - heavy chain 10.1351/goldbook.13198 13198 current synonym: H-chain 1 Larger of the two types of polypeptide chain found in immunoglobulin (Ig) molecules. Each heavy chain is linked by disulfide bonds to a light chain and to another, identical heavy chain. Each heavy chain consists of an Fc fragment and an Fd fragment. Heavy chains carry the antigenic determinants that differentiate the various immunoglobulin classes. Fc fragment https://goldbook.iupac.org/terms/view/13137 Fd fragment https://goldbook.iupac.org/terms/view/13139 PAC, 2012, 84, 1113. 'IUPAC glossary of terms used in immunotoxicology (IUPAC Recommendations 2012)' on page 1173 (https://doi.org/10.1351/PAC-REC-11-06-03) https://goldbook.iupac.org/terms/view/13198/html https://goldbook.iupac.org/terms/view/13198/json https://goldbook.iupac.org/terms/view/13198/plain Citation: 'heavy chain' in IUPAC Compendium of Chemical Terminology, 5th ed. International Union of Pure and Applied Chemistry; 2025. Online version 5.0.0, 2025. 10.1351/goldbook.13198 The IUPAC Gold Book is licensed under Creative Commons Attribution-ShareAlike CC BY-SA 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/) for individual terms. If you are interested in licensing the Gold Book for commercial use, please contact the IUPAC Executive Director at executivedirector@iupac.org . The International Union of Pure and Applied Chemistry (IUPAC) is continuously reviewing and, where needed, updating terms in the Compendium of Chemical Terminology (the IUPAC Gold Book). Users of these terms are encouraged to include the version of a term with its use and to check regularly for updates to term definitions that you are using. 2026-06-27T19:07:02+00:00