PMID: 36921May 23, 1979

Purification and preliminary characterization of two asclepains from the latex of Asclepias syriaca L. (milkweed)

Biochimica Et Biophysica Acta
W J Brockbank, K R Lynn

Abstract

Two groups of asclepains have been isolated from Asclepias syriaca L. (milk-weed) latex and a representative of each has been purified. Asclepains A3 and B5 are homogeneous proteins with molecular weights of 23 000 and 21 000, respectively. Both require a reducing and chelating agent for maximum activity and hydrolyze ester, amide and peptide bonds. The optimum pH for hydrolysis of casein is 7.5 to 8.5 for asclepain A3 and 7.0 to 7.5 for asclepain B5. Both enzymes are autolytic when active and are inhibited by p-chloromercuribenzoate, iodoacetic acid and sodium tetrathionate. Asclepains A3 and B5 each contain one titratable SH group per molecule and no bound carbohydrate. Each of the two enzymes has leucine as the N-terminal amino acid. There are notable differences in their amino acid compositions.

References

Feb 20, 2003·Phytochemistry·Vikash Kumar Dubey, M V Jagannadham
Mar 21, 1998·Bioscience, Biotechnology, and Biochemistry·H YonezawaT Uchikoba
Feb 8, 2016·Applied Biochemistry and Biotechnology·Cynthia SequeirosSebastián A Trejo
Sep 13, 2006·International Journal of Experimental Pathology·Gillian StepekJerzy M Behnke
Aug 21, 1980·Biochimica Et Biophysica Acta·K R LynnC Roy
Nov 15, 1982·Journal of Molecular Biology·U HeinemannW Saenger

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