The two cathepsin B-like proteases of Arabidopsis thaliana are closely related enzymes with discrete endopeptidase and carboxydipeptidase activities.

The genome of the model plant Arabidopsis thaliana encodes three paralogues of the papain-like cysteine proteinase cathepsin B (AtCathB1, AtCathB2 and AtCathB3), whose individual functions are still largely unknown. Here we show that a mutated splice site causes severe truncations of the AtCathB1 polypeptide, rendering it catalytically incompetent. By contrast, AtCathB2 and AtCathB3 are effective proteases which display comparable hydrolytic properties and share most of their substrate specificities.

The death enzyme CP14 is a unique papain-like cysteine proteinase with a pronounced S2 subsite selectivity.

The cysteine protease CP14 has been identified as a central component of a molecular module regulating programmed cell death in plant embryos. CP14 belongs to a distinct subfamily of papain-like cysteine proteinases of which no representative has been characterized thoroughly to date. However, it has been proposed that CP14 is a cathepsin H-like protease.

Glycan modulation and sulfoengineering of anti-HIV-1 monoclonal antibody PG9 in plants.

Broadly neutralizing anti-HIV-1 monoclonal antibodies, such as PG9, and its derivative RSH hold great promise in AIDS therapy and prevention. An important feature related to the exceptional efficacy of PG9 and RSH is the presence of sulfated tyrosine residues in their antigen-binding regions. To maximize antibody functionalities, we have now produced glycan-optimized, fucose-free versions of PG9 and RSH in Nicotiana benthamiana.

Nicotiana benthamiana cathepsin B displays distinct enzymatic features which differ from its human relative and aleurain-like protease.

The tobacco-related plant species Nicotiana benthamiana has recently emerged as a versatile expression platform for the rapid generation of recombinant biopharmaceuticals, but product yield and quality frequently suffer from unintended proteolysis. Previous studies have highlighted that recombinant protein fragmentation in plants involves papain-like cysteine proteinases (PLCPs). For this reason, we have now characterized two major N.