ca·​thep·​sin kə-ˈthep-sən How to pronounce cathepsin (audio)
: any of several intracellular proteases of animal tissue that aid in autolysis

Examples of cathepsin in a Sentence

Recent Examples on the Web Another signaling molecule, cathepsin B, triggers beneficial changes in the brain, including the production of new brain cells. Bob Holmes, Discover Magazine, 26 Dec. 2019 Fortunately, Gerwick had encountered cathepsin inhibitors before. Stephanie Stone, Smithsonian Magazine, 2 Sep. 2021

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'cathepsin.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History


Greek kathepsein to digest (from kata- cata- + hepsein to boil) + English -in entry 2

First Known Use

1929, in the meaning defined above

Time Traveler
The first known use of cathepsin was in 1929

Dictionary Entries Near cathepsin

Cite this Entry

“Cathepsin.” Dictionary, Merriam-Webster, Accessed 27 Feb. 2024.

Medical Definition


ca·​thep·​sin kə-ˈthep-sən How to pronounce cathepsin (audio)
: any of a class of proteases present in most animal tissues (as in kidney, liver, and spleen) that catalyze the hydrolysis of proteins to polypeptides
Cathepsins are lysosomal proteases that cleave their substrates with relatively low specificity.Arthur M. Krieg et al., Science
Recent investigations by several research groups, working with organisms as diverse as worms and monkeys, implicate cathepsins flooding the cytoplasm as a major cause of necrotic cell death.Nektarios Tavernarakis, New Scientist
catheptic adjective
catheptic enzymes
catheptic activity
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