A method for protein extraction from different subcellular fractions of laticifer latex in Hevea brasiliensis compatible with 2-DE and MS

Based on the reported Borax/PVPP/Phenol (BPP) protocol, we developed an efficient method for protein preparation from different latex subcellular fractions and constructed high-resolution reference 2-DE maps. The obtained proteins from both total latex and C-serum fraction with this protocol generate more than one thousand protein spots and several hundreds of protein spots from rubber particles as well as lutoid fraction and its membranes on the CBB stained 2-DE gels. The identification of 13 representative proteins on 2-DE gels by MALDI TOF/TOF MS/MS suggested that this method is compatible with MS.The proteins extracted by this method are compatible with 2-DE and MS. This protein preparation protocol is expected to be used in future comparative proteomic analysis for natural rubber latex.Rubber latex is a specific cytoplasm from laticifer cells located in the secondary phloem of rubber tree (Hevea brasiliensis Muell. Arg.) [1]. It is a milky fluid composed of a liquid serum [2]. In fresh latex, natural rubber occupies 20-60% of total weight [1]. After ultracentrifugation, latex is separated into three major phases including a top layer of rubber particles, a clear cytoplasm called C-serum, and a pellet known as lutoids [1-3]. C-serum represents the aqueous phase of the laticiferous cytoplasmic content, and contains about 60% of whole latex proteins [4,5]. The lutoids play pivotal roles in coagulating of latex and resisting for outside invasion [6,7]. There are two kinds of roughly distinguished rubber particles called small rubber particle (SRP) and large rubber particle (LRP). Both the LRP and SRP have homogeneous and spherical rubber cores enclosed by a layer of semi-unit membrane [3,8,9].Till now, the details of natural rubber biosynthesis mechanism in H. brasiliensis are still long-standing puzzles [2]. With the new advances in technologies for proteomics, many researchers pay much attention for using these novel approaches to characterize new proteins and ou