ABSTRACT
Objective The aim of this study was to establish a rat model of Parkinson''s disease ( PD) by using 6-hydroxydopamine (6-OHDA) and detect the salsolinol N-methyltransferase ( SNMT) activity in peripheral lymphocytes of PD rats for the development of a biomarker for early diagnosis of PD. Methods Rat model of PD was established by unilateral double-pointed injection of 6-OHDA into the striatum and was verified by behavior observation. An analytical method was developed based on multiple reaction monitoring with HPLC-ESI-QQQ to determine the SNMT activity in peripheral lymphocytes. Results Seven of 18 rats injected with 6-OHDA showed steadily apomorphine-induced rotation ( >7 r/min) . The success rate was 38. 9%. A sensitive and stable quantitative method with internal standard added was created, based on multiple reaction monitoring mode to analyze SNMT activity. The limit of detection ( LOD) and limit of quantitation ( LQD) of N-methyl-salsolinol, which is the product of Salsolinol catalyzed by SNMT, were 49 pmol/L and 98 pmol/L, respectively. The precisions of intra-day and inter-day assays both were below 6. 0%. SNMT activity of peripheral lymphocytes in the 6-OHDA-lesioned rats was significantly increased [43. 37 ±9. 49 pmol/(h·mg)NMSal] in comparison with that in the normal group [2. 16 ±5. 82 pmol/(h·mg)NMSal] and the sham-operated group [0. 58 ±2. 32 pmol/(h· mg)NMSal](P< 0. 01, n=5). There was no significant difference between the normal group and sham-operated group (P< 0. 05, n =5). Conclusions Our results indicate that SNMT activity may reflect the changes in the course of Parkison''s disease and may become a potential clinical biomarker in diagnosis of this disease.
ABSTRACT
Isobaric peptide termini labeling ( IPTL) is a technology which uses light and heavy isotopes to label C-terminus and N-terminus of peptides. As the masses of labeled peptides are equivalent, the complexity of sample is low when analyzing MS data produced by this technology. Besides, paired b and y ions are helpful while analyzing MS/MS data in this kind of experiments. On the basis of this, a novel scoring algorithm, all ions scoring algorithm (AISA), has been designed for IPTL experiments. The information of quantification and qualification can be acquired at the same time using AISA. On Q-Exactive HeLa 2D RPLC dataset, peptide spectrum matches ( PSMs) , distinct peptides and protein groups identified by AISA are 15%, 26%and 22% higher than Morpheus. On human-HCC-HL dataset, PSMs, distinct peptides and protein groups identified by AISA are 24%, 39% and 27% higher than Morpheus. Quantification ratio on Q-Exactive HeLa and human-HCC-HL datasets are 1. 18 and 0. 90, respectively, which are very close to 1. Besides, quantification ratios between 0. 5 and 2. 0 are 91% and 94%, respectively.
ABSTRACT
Isobaric peptide termini labeling ( IPTL) is a technology which uses light and heavy isotopes to label C-terminus and N-terminus of peptides. As the masses of labeled peptides are equivalent, the complexity of sample is low when analyzing MS data produced by this technology. Besides, paired b and y ions are helpful while analyzing MS/MS data in this kind of experiments. On the basis of this, a novel scoring algorithm, all ions scoring algorithm (AISA), has been designed for IPTL experiments. The information of quantification and qualification can be acquired at the same time using AISA. On Q-Exactive HeLa 2D RPLC dataset, peptide spectrum matches ( PSMs) , distinct peptides and protein groups identified by AISA are 15%, 26%and 22% higher than Morpheus. On human-HCC-HL dataset, PSMs, distinct peptides and protein groups identified by AISA are 24%, 39% and 27% higher than Morpheus. Quantification ratio on Q-Exactive HeLa and human-HCC-HL datasets are 1. 18 and 0. 90, respectively, which are very close to 1. Besides, quantification ratios between 0. 5 and 2. 0 are 91% and 94%, respectively.