# Sulfo-SPDB (disulfide)

Source: https://onco.cc/terms/sulfo-spdb/  
OnCo record `sulfo-spdb` (Term). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Sulfo-SPDB is a hindered disulfide linker that is stable in blood but is cut by the reducing environment inside cells, then converted to a membrane-crossing form.

## Summary

Sulfo-SPDB attaches DM4 via a sterically hindered disulfide with a charged sulfonate that improves solubility and reduces aggregation. Intracellular glutathione reduces the bond; the released thiol is S-methylated into a neutral metabolite that diffuses to neighbouring cells. Used in mirvetuximab soravtansine.

## Fields

- Kind: Term
- Last checked: 2026-09-09
- Also known as: hindered disulfide linker

## Sources

- Wikipedia: https://en.wikipedia.org/wiki/Mirvetuximab_soravtansine
- Disulfide-linked antibody-maytansinoid conjugates incl. sulfo-SPDB (Kellogg et al., Bioconjugate Chem 2011): https://doi.org/10.1021/bc100480a

## Connected records

- terms: [DM4](https://onco.cc/terms/dm4/), [Linker (ADC)](https://onco.cc/terms/linker/)
- technologies: [Antibody-drug conjugate (ADC)](https://onco.cc/technologies/adc/)
- drugs: [Mirvetuximab soravtansine](https://onco.cc/drugs/mirvetuximab-soravtansine/)
- key papers: [Disulfide-linked antibody-maytansinoid conjugates: optimization of in vivo activity by varying the steric hindrance at carbon atoms adjacent to the disulfide linkage](https://onco.cc/key-papers/paper-kellogg-bioconjug-chem/)

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JSON: https://onco.cc/api/v1/entities/sulfo-spdb.json