Glossary of "Plant Biology (1st ed.)" by Graham et al. (2003)
- A substance that speeds up the rate of a chemical reaction without itself being consumed; enzymes function as catalysts.
Glossary of "The Cell (5th ed.)" by Alberts et al. (2008)
- Substance that can lower the activation energy of a reaction (thus increasing its rate), without itself being consumed by the reaction.
- Alberts, B., Johnson, A., Lewis, J. Raff, M., Roberts, K. & Walter P. 2008. Molecular Biology of the Cell, 5th ed. -xxxiii + 1268 pp. Garland Science, New York.
- Graham, L. E., Graham, J. M. & Wilcox, L. W. 2003. Plant Biology. -xxxv + 497 pp. Pearson Education, Inc., Upper Saddle River.