Glossary of "Plant Biology (1st ed.)" by Graham et al. (2003)
- Proteins that act as biochemical catalysts and regulate the rates at which biological processes occur within cells.
Glossary of "Life (9th ed.)" by Sadava et al. (2011)
- A catalytic protein that speeds up a biochemical reaction.
Glossary of "Evolution of Plants (2nd ed.)" by Willis & McElwain (2014)
- A biological catalyst.
"A Dictionary of Ecology, Evolution and Systematics (2nd ed.)" by Lincoln et al. (1998)
- One of a class of efficient and specific biological catalysts that is composed principally of a globular protein of one or more peptide chains, ranging in molecular weight from around 10 000 to several hundred thousand daltons.
- Graham, L. E., Graham, J. M. & Wilcox, L. W. 2003. Plant Biology. -xxxv + 497 pp. Pearson Education, Inc., Upper Saddle River.
- Lincoln, R., Boxshall, G. & Clark, P. 1998. A Dictionary of Ecology, Evolution and Systematics. ix + 361 pp. Cambridge University Press, Cambridge.
- Sadava, D., Hillis, D. M., Heller, H. C. & Berenbaum, M. R. 2011. Life: The Science of Biology, 9th ed. -xliv + 1266 pp. Sinauer Associates, Inc., Sunderland.
- Willis, K. J. & McElwain, J. C. 2014. The Evolution of Plants, 2nd ed. -ix + 398 pp. Oxford University Press, Oxford.