Recombinant pro-regions from papain and papaya proteinase IV-are selective high affinity inhibitors of the mature papaya enzymes

By jpeza - Posted on 11 Noviembre 2010

Fecha Publicación: 
1 Ene 1995
Nombre de Revista: 
Datos del paper
Página Inicial: 
Página Final: 

Proteolytic enzymes require the presence of their pro-regions for
correct folding. Of the four proteolytic enzymes from Carica papaya,
papain and papaya proteinase IV (PPIV) have 68% sequence identity. We
find that their pro-regions are even more similar, exhibiting 73.6%
identity. cDNAs encoding the pro-regions of these two proteinases have
been expressed in Escherichia coli independently from their mature
enzymes. The recombinant pro-regions of papain and PPIV have been shown
to be high affinity inhibitors of all four of the mature native papaya
cysteine proteinases. Their inhibition constants are in the range 10(-6)
- 10(-9) M. PPIV was inhibited two to three orders of magnitude less
effectively than papain, chymopapain and caricain. The pro-region of
PPIV, however, inhibited its own mature enzyme more effectively than did
the pro-region of papain. Alignment of the sequences of the four papaya
enzymes shows that there is a highly variable section towards the
C-terminal of the pro-region. This region may therefore confer
selectivity to the pro-regions for the individual proteolytic enzymes.

Dirección del Autor: 

Protein Engineering Department, Institute of Food Research, Reading, UK.

Proteolytic enzymes
[file] Protein_Engineering_1995_vol8_(1)_pp59-62.pdf2.21 MB