# Enrichment of Cysteine S-palmitoylated Peptides Using Sodium Deoxycholate Acid Precipitation

## TL;DR

The paper introduces a new method called SDC-ACE for efficiently identifying S-palmitoylated peptides, which helps study their role in cellular processes and diseases like diabetes.

## Contribution

The novel SDC-ACE method enables fast and sensitive enrichment of S-palmitoylated peptides surpassing existing techniques.

## Key findings

- More than 33,000 formerly S-palmitoylated peptides were identified from mouse brain.
- SDC-ACE reveals tissue-specific S-palmitoylation events across mouse organs.
- Regulated S-palmitoylated sites linked to obesity and diabetes were uncovered.

## Abstract

S-palmitoylation is a poorly understood post-translational modification that is gaining more attention as an essential regulator of cellular processes. The reversible nature of S-palmitoylation may allow for fine-tuned control of cellular events and adaptation to stimuli. The detection of S-palmitoylated proteins and peptides includes the Acyl-Biotin Exchange (ABE) method, Acyl resin-assisted Capture (Acyl-RAC), metabolic labelling, and derivatives thereof. We present a novel method of enrichment of S-palmitoylated peptides termed SDC Acid Precipitation Enrichment (SDC-ACE). Here, S-palmitoylated peptides are enriched by taking advantage of their co-precipitation with Sodium deoxycholate (SDC) under acidic conditions, allowing easy and fast separation of lipidated peptides from the sample suspension. We initially applied our novel method for the characterization of the mouse brain, providing an in-depth analysis of S-palmitoylation events within the brain and comprehensive profile of the mouse brain S-palmitoylome. Further, we applied our method for mapping mouse tissue-specific S-palmitoylation, highlighting the extensive role of S-palmitoylation throughout various organs in the body. Finally, we applied our methods for studying the brain palmitoylome of diabetic db/db mouse, uncovering alterations in the palmitoylation of proteins associated with obesity and type 2 diabetes. The SDC-ACE method allows fast and easy enrichment of S-palmitoylated peptides, providing a valuable tool for exploring the dynamics and function of S-palmitoylation in diverse biological systems.

•Sodium Deoxycholate Acid Precipitation efficiently identify S-palmitoylation sites.•SDC-ACE surpasses current methodologies for identifying S-palmitoylated sites.•More than 33,000 formerly S-palmitoylated peptides were identified from mouse brain.•SDC-ACE identify tissue-specific S-palmitoylation events in mice organs.•S-palmitoylation is observed on enzymes involved in regulation of PTMs.•SDC-ACE reveal regulated S-palmitoylated sites linked to obesity linked diabetes.

Sodium Deoxycholate Acid Precipitation efficiently identify S-palmitoylation sites.

SDC-ACE surpasses current methodologies for identifying S-palmitoylated sites.

More than 33,000 formerly S-palmitoylated peptides were identified from mouse brain.

SDC-ACE identify tissue-specific S-palmitoylation events in mice organs.

S-palmitoylation is observed on enzymes involved in regulation of PTMs.

SDC-ACE reveal regulated S-palmitoylated sites linked to obesity linked diabetes.

In this article, we present a novel simple and fast method for enriching and characterizing formerly S-palmitoylated peptides using sodium deoxycholate liquid–solid separation combined with acid precipitation and dithiothreitol reduction (termed the SDC-ACE method). The method surpasses current methodologies for assessing formerly S-palmitoylated peptides with respect to numbers, sensitivity and simplicity. It resulted in the identification of more than 33.000 formerly S-palmitoylated peptides from mouse brain membrane preparations and identification of tissue specific palmitoylation patterns.