Metabolomics Creative Proteomics

Phytosulfokine (PSK) Analysis Service

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PSK, first identified from cultured media of an asparagus suspension culture as a positive growth factor. PSK (PSK-α, PSK-β) belongs to a group of small sulfated plant peptides. PSK-β is a degradation product of PSK-α and exhibits weaker biological activity than PSK-α. PSK is now used as an equivalent term for PSK-α. PSK has been implicated in a wide range of biological processes such as growth regulation, biotic and abiotic stress responses, and reproductive processes. In recent years, liquid chromatography with tandem mass spectrometry (LC–MS/MS)-based analysis method has shown many benefits in the determination of endogenous levels of PSK due to its high sensitivity, accuracy and reproducibility. Creative Proteomics has developed high-efficiency, high throughput sample pretreatment and LC–MS/MS analysis methods for detecting and quantifying the low concentration of PSK in various samples.

Schematic diagram of PSK biosynthesis  Figure 1. Schematic diagram of PSK biosynthesis (Sauter 2015).

Applications of PSK Analysis

  • Revealing the roles of PSK in plant biological processes
  • Elucidating the PSK biosynthesis mechanisms and metabolic pathways
  • Understanding PSK signal transduction and signal transmission
  • Promoting the application of PSK in agricultural production

Advantages of Our PSK Analysis Service

High sensitivity, accuracy and reproducibility

High-resolution LC-MS analytical method using MRM acquisition mode

Decades of experience in plant hormone analysis

Fast turnaround time and competitive price

Service Workflow

Creative Proteomics provides a highly sensitive and selective method for detecting and quantifying rare PSK in plants using LC-MS/MS. We have extensive experience in dealing with a variety of sample types, and ensure to achieve the best recovery and ideal LC–MS/MS detection along with reduced background noise.

Phytosulfokine (PSK) Analysis Service

Quantitation method: external standard method

Analysis content:

  • Raw data preprocessing
  • Absolute quantitation of PSK
  • Differential metabolites screening
  • Partial least squares-discriminant analysis (PLS-DA) and principle component analysis (PCA)

List of Detectable PSK at Creative Proteomics

Detectable PSKCASQuantitation Method
PSK/External standard method

Sample Requirements

Fresh plant tissues > 1 g. Samples should be frozen in liquid nitrogen right after collection, and then transferred to -80°C for storage.

At least 3 biological replicates.


  • Experimental procedure
  • Parameters of LC-MS
  • MS raw data files and MS data quality checks
  • PSK quantification data
  • Custom bioinformatics analysis report

Creative Proteomics is proud to have been offering a complete battery of plant hormone analysis services, contributing to elucidating the functions, biological synthesis, metabolism, and networks of phytohormones. With decades of experience, efficiency and internal standards, we ensure reliable and economical results.


  1. Sauter M. Phytosulfokine peptide signalling. Journal of Experimental Botany, 2015, 66(17): 5161-5169.
  2. Kiełkowska A, Adamus A. Peptide growth factor phytosulfokine-α stimulates cell divisions and enhances regeneration from B. oleracea var. capitata L. Protoplast Culture. Journal of Plant Growth Regulation, 2019, 38(3): 931-944.
  3. Xin P, Guo Q, Li B, et al. A tailored high-efficiency sample pretreatment method for simultaneous quantification of 10 classes of known endogenous phytohormones. Plant communications, 2020, 1(3): 100047.
For Research Use Only. Not for use in diagnostic procedures.


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