Brain Cathepsin B Cleaves a Caspase Substrate

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A. A. Yakovlev^1,2, A. Yu. Gorokhovatsky³, M. V. Onufriev¹, I. P. Beletsky², and N. V. Gulyaeva^1*

¹Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, ul. Butlerova 5a, 117485 Moscow, Russia; E-mail: nata_gul@pisem.net

²Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, ul. Institutskaya 3, 142290 Pushchino, Moscow Region, Russia

³Institute of Bioorganic Chemistry, Pushchino Branch, Russian Academy of Sciences, pr. Nauki 6, 142290 Pushchino, Moscow Region, Russia

^* To whom correspondence should be addressed.

Received June 20, 2007; Revision received August 6, 2007

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We show that an enzyme exists in rat brain capable of cleaving the caspase-3 specific peptide substrate Ac-DEVD-AMC at low pH. The enzyme shows properties of a cysteine protease and is localized, predominantly, in lysosomes. We have purified this enzyme from rat brain and identified it by MALDI-TOF MS. The enzyme possessing “acidic” DEVDase activity in rat brain appears to be cathepsin B. It remains obscure, whether cathepsin B participates in cleavage of caspase-3 substrates in vivo. We suggest that under certain conditions (e.g. in hypoxia) cathepsin B participates in cleavage of caspase-3 substrates in brain cells.

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KEY WORDS: caspase-3, cathepsin B, Ac-DEVD-AMC

DOI: 10.1134/S0006297908030140

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