Recent advances in sample pre-treatment for emerging methods in proteomic analysis

Phosphopeptide enrichment for phosphoproteomic analysis - A tutorial and review of novel materials

Significant technical advancements in phosphopeptide enrichment have enabled the identification of thousands of p-peptides (mono and multiply phosphorylated) in a single experiment. However, it is still not possible to enrich all p-peptide species in a single step. A range of new techniques and materials has been developed, with the potential to provide a step-change in phosphopeptide enrichment. The first half of this review contains a tutorial for new potential phosphoproteomic researchers; discussing the key steps of a typical phosphoproteomic experiment used to investigate canonical phosphorylation sites (serine, threonine and tyrosine). The latter half then show-cases the latest developments in p-peptide enrichment including: i) Strategies to mitigate non-specific binding in immobilized metal ion affinity chromatography and metal oxide affinity chromatography protocols; ii) Techniques to separate multiply phosphorylated peptides from monophosphorylated peptides (including canonical from non-canonical phosphorylated peptides), or to simultaneously co-enrich other post-translational modifications; iii) New hybrid materials and methods directed towards enhanced selectivity and efficiency of metal-based enrichment; iv) Novel materials that hold promise for enhanced phosphotyrosine enrichment. A combination of well-understood techniques and materials is much more effective than any technique in isolation; but the field of phosphoproteomics currently requires benchmarking of novel materials against current methodologies to fully evaluate their utility in peptide based proteoform analysis.

Facile synthesis of titanium(IV) ion-immobilized poly-glycidyl methacrylate microparticles functionalized with polyethylenimine and adenosine triphosphate for highly specific enrichment of intact phosphoproteins

In this study, a facile synthesis of the titanium(IV) ion-immobilized poly-glycidyl methacrylate microparticles functionalized with polyethylenimine and adenosine triphosphate was developed for efficient enrichment of intact phosphoproteins. The titanium(IV) ion-immobilized microparticles had higher saturated adsorption capacity for phosphoproteins (1217.6 mg/g for β-casein) than nonphosphoproteins (97.1 mg/g for bovine serum albumin) and the average particle diameter was about 1.4 μm with good dispersibility. In application, as demonstrated by SDS-PAGE, titanium(IV) ion-immobilized microparticles exhibited good performance in enriching intact phosphoproteins from standard protein mixtures of β-casein and bovine serum albumin with high specificity and selectivity. In addition, titanium(IV) ion-immobilized microparticles were also successfully applied in intact phosphoprotein enrichment from complex biological samples including nonfat milk, chicken egg white, and mouse heart tissue extract.

Cook Your Samples: The Application of Microwave Irradiation in Speeding Up Biological Processes

Classic and conventional procedures in molecular cloning are inherent compositions in modern molecular biological experiments and are frequently involved in daily laboratory activities. They take up the majority of the total time input in spite of the availability of well-designed specialized commercial kits. A similar situation is also in the field of biotechnology. Fortunately, microwave/ultrasonic irradiation has been found to be capable of speeding up these processes, such as proteolysis in sample preparation for proteomics research, and digestion, ligation, (de)phosphorylation of DNA with the corresponding enzymes, even the introduction of DNA samples to recipient cells, and biotransformation (e.g., the production of biodiesel). Microwave/ultrasonic irradiation, when used solely or in combination with other existing operations, makes it possible to finish these time-consuming processes in as short as 1 min with comparable or even improved efficiency, and there is no need of reagent upgradation. The adoption of irradiation is ideal because it eliminates any possible side effects of the chemicals used as performance enhancer(s) that will inevitably make the system more complicated at least. More notably, the needed irradiation in the laboratory can be generated by a common microwave oven or ultrasonic cleaner. Taken together, microwave/ultrasonic irradiation provides an accessible method to make the procedures mentioned above time- and cost- efficient. In this article, we reviewed the relevant literature and discussed the experiment and mechanism details.