Enzymatic activities and protein profile of latex from Calotropis procera.
The laticifer fluid of Calotropis procera is rich in proteins and there is evidence that they are involved in the pharmacological properties of the latex. However, not much is known about how the latex-containing proteins are produced or their functions. In this study, laticifer proteins of C. procera were pooled and examined by 1D and 2D electrophoresis, masses spectrometry (MALDI-TOF) and characterized in respect of proteolytic activity and oxidative enzymes. Soluble laticifer proteins were predominantly composed of basic proteins (PI>6.0) with molecular masses varying between 5 and 95 kDa. Proteins with a molecular mass of approximately 26,000 Da were more evident. Strong anti-oxidative activity of superoxide dismutase (EC 1.15.1.1) (1007.74+/-91.89 Ug(-1)DM) and, to a lesser extent ascorbate peroxidase (EC 1.11.1.1) (0.117(d)+/-0.013 microMol H(2)O(2)g(-1)min(-1)), were detected. However, catalase (EC 1.11.1.6) was absent. The strong proteolytic activities of laticifer proteins from C. procera were shown to be shared by at least four distinct cysteine proteinases (EC 3.4.22.16) that were isolated by gel filtration chromatography. Serine and metaloproteinases were not detected and aspartic proteinase activities were barely visible. Chitinases (EC 3.2.1.14) were also isolated in a chitin column and their activities quantified. The presence of these enzymatic activities in latex from C. procera may confirm their involvement in resistance to phytopathogens and insects, mainly in its leaves where the latex circulates abundantly.
Freitas
Cleverson Diniz T
CD
Departamento de Bioquímica e Biologia Molecular da Universidade Federal do Ceará, Campus do Pici, Cx. Postal 6033, Fortaleza, Ceará CEP 60451-970, Brazil.
Oliveira
Jefferson Soares
JS
Miranda
Maria Raquel A
MR
Macedo
Nívea Maria R
NM
Sales
Maurício Pereira
MP
Villas-Boas
Laurival A
LA
Ramos
Márcio Viana
MV
D060387:Ascorbate Peroxidases; D031107:Calotropis / Q000378:metabolism*; D002686:Chitin / Q000737:chemistry / Q000378:metabolism; D002688:Chitinases / Q000737:chemistry / Q000378:metabolism; D002846:Chromatography, Affinity; D003546:Cysteine Endopeptidases / Q000737:chemistry / Q000378:metabolism; D015180:Electrophoresis, Gel, Two-Dimensional; D004591:Electrophoresis, Polyacrylamide Gel; D007840:Latex / Q000737:chemistry / Q000378:metabolism*; D008970:Molecular Weight; D010544:Peroxidases / Q000737:chemistry / Q000378:metabolism; D010940:Plant Proteins / Q000737:chemistry / Q000378:metabolism*; D011522:Protons; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013482:Superoxide Dismutase / Q000737:chemistry / Q000378:metabolism; D013696:Temperature
D007840:Latex; D010940:Plant Proteins; D011522:Protons; D002686:Chitin; D010544:Peroxidases; D060387:Ascorbate Peroxidases; D013482:Superoxide Dismutase; D002688:Chitinases; D003546:Cysteine Endopeptidases