[Application of reversed-phase liquid chromatography-tandem mass spectrometry in the identification of protein and bioactivity peptides from rape bee pollen].

Based on the shotgun proteomic method, rape bee pollen protein was prepared with ultrasonic extraction and digested by trypsin, then separated and sequenced by reversed-phase liquid chromatography-tandem mass spectrometry (RPLC-MS/MS), followed by protein database searching. After the above analysis, 353 peptides were identified and the molecular biological functions of 239 proteins have been known. The identified molecular biological functions of these proteins mainly included binding activity, enzyme activity, transporter activity, inhibitor activity and so on. Five peptides were obtained after the screening and appropriate amino acid modification among the identified 353 peptides, according to the relationship between the sequence structure of the bioactivity peptide and angiotensin converting enzyme (ACE) inhibitor activity. The five peptides were speculated to have ACE inhibitor activity and synthesized to detect ACE inhibitor activity. The results showed that all of the five peptides had good ACE inhibitor activity. The peptides of AELDIVLALF and LAVNLIPFP among the five peptides displayed especially good ACE inhibition with half maximal inhibitory concentration (IC50) of (10.65 +/- 0.50) micromol/L and (23.66 +/- 1.08) micromol/L, respectively. This method is rapid, low-cost and achieves the goal of high-throughput screening of bioactivity peptides that greatly shorten the period of identification compared with traditional methods.

[Analysis of proteins in the extracts of Physalis alkekengi L. var. franchetii (Mast.) Makino using nanoflow reversed-phase liquid chromatography-tandem mass spectrometry].

The protein was extracted from Physalis alkekengi L. var. franchetii (Mast.) Makino fruit by using water extraction and acid precipitation methods, and it consisted of 188 mg/g of protein on dry basis of the extract. Among 18 amino acids, eight essential amino acids for human account for 31% were found in this extract. Based on shotgun proteomics method, the protein extracted from Physalis fruit was analysed by nanoflow reversed-phase liquid chromatography-tandem mass spectrometry (nano-RPLC-MS/MS) system. Combined with database searches and bioinformatics analysis, the protein species and six molecular functions were identified, including with catalytic activity, antioxidant activity, enzyme regular activity, nutrient reservoir activity, transporter activity and binding activity. And three antioxidant activity-related proteins were identified. These results may lay the foundation for further study of the functional properties of the proteins in Physalis fruit.