# Serum Proteinogram in the Free‐Living Brazilian Common Opossum (Didelphis aurita)

## TL;DR

This study analyzed the serum proteins of free-living Brazilian common opossums to understand how health, sex, and age affect their protein profiles.

## Contribution

The study identifies specific serum protein bands associated with health status, sex, and age in Didelphis aurita.

## Key findings

- Eighteen serum protein bands were identified with molecular weights ranging from 24 to 242 kDa.
- Variations in specific protein bands were linked to health status, sex, and age of the opossums.
- Seven proteins were identified using mass spectrometry, including DM64 and ceruloplasmin.

## Abstract

Didelphis aurita is a synanthropic marsupial widely distributed in southeastern Brazil, known for its resistance to venom and its relevance in biomedical research. This study aimed to characterize the serum proteinogram of free‐living D. aurita individuals. Blood samples from 27 animals, classified as “healthy” or “diseased,” were analyzed. Eighteen protein bands were identified, with molecular weights ranging from 24 to 242 kDa. Among these, variations in specific bands were associated with health status (band J), sex (bands D, M, N, and P), and age (bands N and P). Mass spectrometry (liquid chromatography–tandem mass spectrometry [LC–MS/MS]) identified seven proteins, including DM64, ceruloplasmin, von Willebrand factor A (VWFA) domain protein, alpha‐2‐macroglobulin, fibronectin, and actin depolymerizing factor. These results highlight the influence of biological factors on serum protein profiles and reinforce the potential of D. aurita as a model for immunological and proteomic studies.