Surface-enhanced Raman scattering-based detection of plasmin activity by specific peptide substrate

Area of Science:

• Biochemistry
• Analytical Chemistry
• Spectroscopy

Background:

• Plasmin is a key enzyme in various biological processes, including food spoilage.
• Accurate detection of plasmin activity is crucial for quality control in the dairy industry.
• Existing methods for plasmin detection may lack sensitivity or require complex procedures.

Purpose of the Study:

• To develop a novel surface-enhanced Raman scattering (SERS)-based method for sensitive plasmin activity detection.
• To optimize SERS substrates using specific peptide sequences for plasmin.
• To validate the method's performance for plasmin detection in real-world samples like milk.

Main Methods:

• Screening of plasmin-specific peptide sequences for SERS substrate preparation.
• Utilizing Raman spectroscopy to monitor the reduction of a DTNB band (1331 cm⁻¹) indicative of plasmin activity.
• Correlating changes in SERS intensity with varying plasmin concentrations.

Main Results:

• The developed SERS method demonstrated a limit of detection (LOD) of 2.14 U/mL and a limit of quantification (LOQ) of 6.42 U/mL.
• Excellent repeatability was observed with intra-day and inter-day relative standard deviations (RSD) of 1.45% and 1.47%, respectively.
• Successful recovery of plasmin activity was achieved in spiked milk samples, indicating method robustness.

Conclusions:

• The proposed SERS-based method provides a sensitive and reliable approach for detecting plasmin activity.
• The method shows significant potential for application in the quality control of dairy products.
• This technique offers a valuable tool for enzyme activity monitoring in complex biological matrices.