Note: All tissues (SILAC and SILAM) can be prepared in the lyophilized form. If you can't find your product in the webshop, please contact us .
Silantes has recently developed a cost-efficient alternative to the 13C-lysine(6) labelled spike-in wet reference in the form of a 13C-lysine(6) labelled lyophilized reference.
This improves the handling of the reference and is more convenient for quantifying protein patterns of single mouse organs.
The in-vivo SILAC Lyo-mouse kit
The lyophilized reference is a ready-to-use sample. It contains 13C-lysine labelled tissue from the respective mouse organ, such as liver, brain, etc. The sample contains about 100 µg of protein which is sufficient for about 3 experiments. The proteins are extracted either with SDS or urea.
Improved handling with unchanged high quality
Silantes conducted a comparative study of wet and lyophilized references in cooperation with Prof. Marcus Krüger from Max Planck Institute for Heart and Lung Research.
The results show that the wet sample can be replaced by the lyophilized sample without loss of accuracy.
Figure 2 shows the analysis of the SDS gel patterns of wet liver (STD) and lyophilized liver (Lyo).
Figure 1: Figure 1: SDS-PAGE of liver tissue samples: Standard (wet liver) and Lyo. (lyophilized liver)
To verify that lyophilization does not change the protein content with respect to the wet sample, both samples were analyzed by mass spectrometry and their peptide patterns were compared.
Please find the results of this analysis below:
Figure 2: Ratio of labelled (H) to unlabelled (L) peptides of the STD and Lyo.
Figure 2: Row (1) shows the ratio of 13C-labelled (H) to unllabeled (L) peptides of the wet sample (STD); Row (2) shows the same for the lyophilized tissue (Lyo.) and row (3) shows the direct comparison of “STD.” and “Lyo.”.
A comparison of the data in row (1) and row (2) shows that the peptide distributions of “STD” and “Lyo.” have a high degree of similarity.
An even greater similarity is observed if wet tissue and lyophilized tissue are directly compared in row (3).
Figure 3 shows a correlation plot using the same data as in Figure 2.
Figure 3: Correlation plot of labelled (H) to unlabelled (L) peptides of the STD and Lyo.
The pearson correlation coefficient of 0.83 indicates a high level of correlation between the peptide data sets from the wet tissue (STD) and the lyophilized tissue (Lyo.), supporting the view that lyophilized tissue is a suitable alternative to the wet tissue.
Figure 4 shows the correlation with the same samples as above, namely the wet liver (STD) and the lyophilized liver (Lyo.), including a new unrelated liver sample (#2) in wet and lyophilized form.
Figure 4: Correlation plot including a new liver sample in wet and lyophilized form
As expected, the data show a lower correlation of #1 with respect to #2 indicating that differences between unrelated liver samples can be detected.