TY - JOUR
T1 - Characterization of the exopeptidase activity existing in Theobroma cacao L. during germination
AU - Sánchez-Mundo, M. L.
AU - Bautista-Muñoz, C.
AU - Jaramillo-Flores, M. E.
PY - 2010/7
Y1 - 2010/7
N2 - The present work reports exopeptidase activity existing in cacao (Theobroma cacao L.) during germination. Aminopeptidase (APE), carboxypeptidase (CP) and Xaa-Prolyl dipeptidyl aminopeptidase (Xaa-Pro-DAP) membrane-bound enzymes have been identified. The Xaa-Pro-DAP enzyme (E.C. 3.4.14.5) had not been previously detected in germinating cacao seeds. Xaa-Pro-DAP was partially purified and characterized, and the highest activity was found after 10 days of germination. Xaa-Pro-DAP was isolated by precipitation with 40% ammonium sulfate and partially purified with two chromatographic steps. The enzyme had a relative molecular weight of 80kDa as determined by Native-PAGE and was, able to use Ala-Pro-4μβNA as substrate. In the presence of SDS, this enzyme did not show activity because it must be in a trimer to be functional. Its activity was inhibited 44% by the chelating agent EDTA and 48% by the serine peptidase inhibitor PMSF at 0.1mM, indicating that the partially purified Xaa-Pro-DAP is a serine metallopeptidase. The cations Cu2+ and Cd2+ caused 44% and 67% inhibition, respectively, while the other divalent cations tested had no significant effect on the activity of the partially purified enzyme. The enzyme showed a high specificity for Ala-Pro-pNA as a proteolytic substrate.
AB - The present work reports exopeptidase activity existing in cacao (Theobroma cacao L.) during germination. Aminopeptidase (APE), carboxypeptidase (CP) and Xaa-Prolyl dipeptidyl aminopeptidase (Xaa-Pro-DAP) membrane-bound enzymes have been identified. The Xaa-Pro-DAP enzyme (E.C. 3.4.14.5) had not been previously detected in germinating cacao seeds. Xaa-Pro-DAP was partially purified and characterized, and the highest activity was found after 10 days of germination. Xaa-Pro-DAP was isolated by precipitation with 40% ammonium sulfate and partially purified with two chromatographic steps. The enzyme had a relative molecular weight of 80kDa as determined by Native-PAGE and was, able to use Ala-Pro-4μβNA as substrate. In the presence of SDS, this enzyme did not show activity because it must be in a trimer to be functional. Its activity was inhibited 44% by the chelating agent EDTA and 48% by the serine peptidase inhibitor PMSF at 0.1mM, indicating that the partially purified Xaa-Pro-DAP is a serine metallopeptidase. The cations Cu2+ and Cd2+ caused 44% and 67% inhibition, respectively, while the other divalent cations tested had no significant effect on the activity of the partially purified enzyme. The enzyme showed a high specificity for Ala-Pro-pNA as a proteolytic substrate.
KW - Germination
KW - Peptidase
KW - Theobroma cacao L.
KW - Xaa-Prolyl dipeptidyl aminopeptidase
UR - http://www.scopus.com/inward/record.url?scp=77954815757&partnerID=8YFLogxK
U2 - 10.1016/j.procbio.2010.04.012
DO - 10.1016/j.procbio.2010.04.012
M3 - Artículo
SN - 1359-5113
VL - 45
SP - 1156
EP - 1162
JO - Process Biochemistry
JF - Process Biochemistry
IS - 7
ER -