# Aqueous alkaline phosphate facilitates the non-exchangeable deuteration of peptides and proteins

## TL;DR

This paper introduces a new method to add deuterium to stable parts of peptides and proteins using alkaline phosphate, useful for drug development and structural studies.

## Contribution

A late-stage deuteration method targeting non-exchangeable backbone sites using aqueous alkaline phosphate is introduced.

## Key findings

- Deuteration of non-exchangeable backbone sites is achieved using an alkaline phosphate solution.
- The method shows site and structure selectivity, especially for α-helix regions in myoglobin.
- The technique works well for peptides and proteins stable under high pH conditions.

## Abstract

The incorporation of deuterium into peptides and proteins holds broad applications across various fields, such as drug development and structural characterization. Nevertheless, current methods for peptide/protein deuteration often target exchangeable labile sites or require harsh conditions for stable modification. In this study, we present a late-stage approach utilizing an alkaline phosphate solution to achieve deuteration of non-exchangeable backbone sites of peptides and proteins. The specific deuteration regions are identified through ultraviolet photodissociation (UVPD) and mass spectrometry analysis. This deuteration strategy demonstrates site and structure selectivity, with a notable affinity for labeling the α-helix regions of myoglobin. The deuterium method is particularly suitable for peptides and proteins that remain stable under high pH conditions.

The incorporation of deuterium into peptides and proteins holds broad applications across various fields, such as drug development and structural characterization.