A new cysteine endopeptidase (morrenain b I) has been purified and characterized from the latex of stems and petiols of Morrenia brachystephana Griseb. (Asclepiadaceae). Morrenain b I was the minor proteolytic component in the latex but showed higher specific activity than morrenain b II, which was the main active fraction. Both enzymes showed similar pH profiles and molecular masses, but kinetic parameters and N-terminal sequences were quite distinct, demonstrating that they are different enzymes instead of different forms of the same enzyme.
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http://dx.doi.org/10.1023/a:1023059525861 | DOI Listing |
J Evol Biol
April 2014
Laboratorio de Ecología Evolutiva - Biología Floral, Instituto Multidisciplinario de Biología Vegetal (IMBIV), CONICET-Universidad Nacional de Córdoba, Córdoba, Argentina.
Pollinator-mediated natural selection on single traits, such as corolla tube or spur length, has been well documented. However, flower phenotypes are usually complex, and selection is expected to act on several traits that functionally interact rather than on a single isolated trait. Despite the fact that selection on complex phenotypes is expectedly widespread, multivariate selection modelling on such phenotypes still remains under-explored in plants.
View Article and Find Full Text PDFAnn Bot
January 2012
Laboratorio de Biología Floral (IMBIV-CONICET-UNCba), CC 495, CP 5000, Córdoba, Argentina.
Unlabelled: BACKGROUND AND AIMS The extreme complexity of asclepiad flowers (Asclepiadoideae-Apocynaceae) has generated particular interest in the pollination biology of this group of plants especially in the mechanisms involved in the pollination processes. This study compares two South American species, Morrenia odorata and Morrenia brachystephana, with respect to morphology and anatomy of flower structures, dynamic aspects of the pollination mechanism, diversity of visitors and effectiveness of pollinators.
Methods: Floral structure was studied with fresh and fixed flowers following classical techniques.
J Protein Chem
January 2003
LIPROVE, Departamento de Ciencias Biológicas, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, C.C. 711, B1900AVW La Plata, Argentina.
A new cysteine endopeptidase (morrenain b I) has been purified and characterized from the latex of stems and petiols of Morrenia brachystephana Griseb. (Asclepiadaceae). Morrenain b I was the minor proteolytic component in the latex but showed higher specific activity than morrenain b II, which was the main active fraction.
View Article and Find Full Text PDFBiol Chem
May 2001
Departamento de Ciencias Biológicas, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, Argentina.
The properties of morrenain b II, a proteinase isolated from the latex of Morrenia brachystephana, were compared with those of morrenain o II, a proteinase obtained from the latex of Morrenia odorata. Both peptidases were purified to homogeneity by acetone precipitation followed by cation exchange chromatography. The enzymes have pI values higher than 9.
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