ABSTRACT
OBJECTIVE: The aim of the study was to evaluate proline metabolism in patients affected by COVID-19. MATERIALS AND METHODS: This case-control study consisted of 116 patients with COVID-19 and 46 healthy individuals. Tests related to proline metabolism (prolidase, proline, hydroxyproline, glutamic acid, manganese) and copper and zinc tests were analyzed. RESULTS: The levels of proline and hydroxyproline amino acids and the prolidase enzyme were found to be lower and glutamic acid was found to be higher in the COVID-19 group compared to the healthy group (Pâ =â .012, Pâ < .001, Pâ < .001, and Pâ < .001, respectively). The copper/zinc ratio was higher in patients with COVID-19 than in healthy individuals (Pâ < .001). Significant correlations were found between proline metabolism tests and inflammatory and hemostatic markers commonly used in COVID-19. CONCLUSION: The proline metabolic pathway was affected in COVID-19. Relationships between proline pathway-related tests and inflammatory/hemostatic markers supported the roles of proline metabolism in proinflammatory and immune response processes.