Isolation and purification of cysteine peptidases from the latex of Araujia hortorum fruits - Study of their esterase activities using partial least-squares (PLS) modeling
N. Priolo et al., Isolation and purification of cysteine peptidases from the latex of Araujia hortorum fruits - Study of their esterase activities using partial least-squares (PLS) modeling, J MOL CAT B, 15(4-6), 2001, pp. 177-189
Three new cysteine peptidases (araujiain h-I, araujiain h-II and araujiain
h-III) were isolated and purified to mass spectroscopy homogeneity from the
latex of Araujia hortorum (Asclepiadaceae) fruits by ultracentrifugation a
nd ion exchange chromatography. The enzymes have molecular masses of 24,030
.87, 23,718 and 23,545.5 (mass spectrometry), respectively. The peptidases
were activated by thiol compounds and inhibited by common thiol blocking re
agents, particularly E-64 and HgCl2, suggesting that the enzymes belong to
the cysteine peptidases family. A quantitative structure-activity relations
hip study of their esterolytic activities was performed by means of partial
least-squares regression and using the novel filtering technique called or
thogonal signal correction. The numerical characterization of the variation
in the physicochemical features of the N-alpha -carbobenzoxy-aminoacid-p-n
itrophenyl esters used in the PLS regression modeling was accomplished by u
sing a large number of descriptors extracted from the literature, based on
various lipophilicity, polarity and steric scales of the amino acid side-ch
ains in combination with a set of property descriptors derived from semiemp
irical calculations. From the obtained results it can be concluded that all
hydrophobic, electronic, and steric factors are important in the esterase
activity of the cysteine peptidases studied. (C) 2001 Elsevier Science B.V.
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