New insights into the complex mixture of latex cysteine peptidases in Calotropis procera

Abstract

The latex of Calotropis procera is a rich source of proteolytic activity. This latex is known to contain two distinct cysteine peptidases: procerain and procerain B. In this study, new cysteine peptidases were purified from C. procera latex. The enzymes were purified by two sequential ion-exchange chromatography steps (CM-Sepharose plus Resource S(®)) at pH 5.0 and 6.0. The purified enzymes had molecular mass spectra corresponding to CpCP-1=26,213, CpCP-2=26,133 and CpCP-3=25,086 Da. These enzymes exhibited discrete differences in terms of enzymatic activity at a broad range of pH and temperature conditions and contained identical N-terminal amino acid sequences. In these respects, these three new proteins are distinct from those previously studied (procerain and procerain B). Circular dichroism analysis revealed that the new peptidases contain extensive secondary structures, α(15-20%) and β(26-30%), that were stabilized by disulfide bonds. The purified enzymes exhibited plasma-clotting activity mediated by a thrombin-like mechanism. The set of results suggest the three isolated polypeptides correspond to different post-translationally processed forms of the same protein.

Insights into milk-clotting activity of latex peptidases from Calotropis procera and Cryptostegia grandiflora

“…Latex fluids have been described as rich sources of cysteine and serine peptidases (Domsalla & Melzing, 2008). In the latex fluids of C. papaya (Azarkan, El Moussaoui, van Wuytswinkel, Dehon, & Looze, 2003), C. procera and C. grandiflora only cysteine peptidases have been described, whereas in P. rubra latex there is a mixture of serine and cysteine peptidases (Freitas et al, 2010;Ramos, Araújo, Jucá, Monteiro-Moreira, & Vasconcelos, 2013).…”

A novel form of ficin from Ficus carica latex: Purification and characterization

“…The properties of latex in plant defense and in alleviating various diseases have been attributed to the presence of several hydrolytic enzymes from which proteases play a key role. Most of the proteases found in latex of different plants belong to cysteine and serine proteases families (Singh et al, 2008;El Moussaoui et al, 2001;Azarkan et al, 2004Azarkan et al, , 2011Torres et al, 2012;Ramos et al, 2013;Yariswamy et al, 2013). Why latex contains high amounts of such proteases still remain enigmatic.…”

Proteinase activity in latex of three plants of the family Euphorbiaceae

“…In latex, the majority of proteases with considerable commercial importance are from cysteine type, such as papain, which is one of the most studied peptidases and is commercially available (El Moussaoui et al, 2001). Also, the latex of Calotropis procera has two known cysteine proteases (procerain and procerain B) and recently a new enzyme was purified from this latex (Ramos et al, 2013). However, serine proteases are found in the latex of Euphorbiaceae.…”