**6. Conclusions**

Erythrocytes, as oxygen carrier cells, are highly exposed to oxidative injury; to face this challenge, RBCs are well equipped with an efficient antioxidant system, important to maintain erythrocyte homeostasis during its life span. The antioxidant system includes non-enzymatic and enzymatic agents such as peroxidases, namely Prx2, GPx and CAT. The role and interplay between these enzymes that prevent H2O2 accumulation in the erythrocyte has been a topic of discussion over the years. So far, it appears that their role depends on the H2O2 levels within RBC: CAT is crucial for scavenging high exogenous and endogenous peroxide levels, GPx and Prx2 are important for scavenging low endogenous and low peroxide levels. GPx and Prx2 are also able to detoxify the cell from organic peroxides, unlike CAT that does not show this function. Therefore, GPx and Prx2 can have a direct role on RBC membrane antioxidant defense.

Several authors have already reported the linkage of CAT, GPx and Prx2 to the erythrocyte membrane in case of metabolic stress and/or OS. In fact, the recruitment of the three peroxidases to the RBC membrane has been described in OS-associated conditions, by in vitro assays and by studies with stored RBCs under blood bank conditions.

Studies about Prx2 reveal a dual function in RBC defense, as a peroxidase and as an Hb chaperone preventing metHb aggregation. Some authors have also proposed that Prx2 may have a major role in erythropoiesis.

Erythrocytes are the ultimate antioxidant defense against the harmful effects of OS in humans; so, the knowledge about the RBC antioxidant system has evolved over time, and should continue to grow, focusing on the importance of CAT, GPx and Prx2 working together in ROS detoxification and also their potential role in the erythrocyte membrane.

### **Acknowledgements**

Financial support from FCT/MCTES through national funds UID/ MULTI/04378/2019 and Norte Portugal Regional Coordination and Development Commission (CCDR-N)/NORTE2020/Portugal 2020 (Norte-01-0145- FEDER-000024) and a PhD grant (SRRH/BD/139622/2018) attributed to D. Melo.

**77**

**Author details**

Daniela Melo1

provided the original work is properly cited.

, Susana Rocha1

2 UCIBIO, REQUIMTE, Porto, Portugal

Technologies (IINFACTS), Gandra-Paredes, Portugal

\*Address all correspondence to: assilva@ff.up.pt

*Interplay between Erythrocyte Peroxidases and Membrane*

*DOI: http://dx.doi.org/10.5772/intechopen.83590*

© 2019 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

1 UCIBIO, REQUIMTE, Laboratory of Biochemistry, Department of Biological

3 CESPU, Institute of research and Advanced Training in Health Sciences and

Sciences, Faculty of Pharmacy, University of Porto, Porto, Portugal

, Susana Coimbra2,3 and Alice Santos Silva1

\*

## **Conflict of interest**

The authors report no conflict of interest.

*Interplay between Erythrocyte Peroxidases and Membrane DOI: http://dx.doi.org/10.5772/intechopen.83590*

*Erythrocyte*

**6. Conclusions**

membrane antioxidant defense.

that Prx2 may have a major role in erythropoiesis.

The authors report no conflict of interest.

blood bank conditions.

erythrocyte membrane.

**Acknowledgements**

**Conflict of interest**

Studies of stored RBCs in blood bank conditions also reported the recruitment of Prx2, CAT and GPx to the RBC membrane due to OS modifications resulting

Data in literature suggest that the linkage of these RBC cytosolic enzymes to the membrane is triggered by metabolic stress, possibly, to protect the erythrocyte

Erythrocytes, as oxygen carrier cells, are highly exposed to oxidative injury; to face this challenge, RBCs are well equipped with an efficient antioxidant system, important to maintain erythrocyte homeostasis during its life span. The antioxidant system includes non-enzymatic and enzymatic agents such as peroxidases, namely Prx2, GPx and CAT. The role and interplay between these enzymes that prevent H2O2 accumulation in the erythrocyte has been a topic of discussion over the years. So far, it appears that their role depends on the H2O2 levels within RBC: CAT is crucial for scavenging high exogenous and endogenous peroxide levels, GPx and Prx2 are important for scavenging low endogenous and low peroxide levels. GPx and Prx2 are also able to detoxify the cell from organic peroxides, unlike CAT that does not show this function. Therefore, GPx and Prx2 can have a direct role on RBC

Several authors have already reported the linkage of CAT, GPx and Prx2 to the erythrocyte membrane in case of metabolic stress and/or OS. In fact, the recruitment of the three peroxidases to the RBC membrane has been described in OS-associated conditions, by in vitro assays and by studies with stored RBCs under

Studies about Prx2 reveal a dual function in RBC defense, as a peroxidase and as an Hb chaperone preventing metHb aggregation. Some authors have also proposed

Erythrocytes are the ultimate antioxidant defense against the harmful effects of OS in humans; so, the knowledge about the RBC antioxidant system has evolved over time, and should continue to grow, focusing on the importance of CAT, GPx and Prx2 working together in ROS detoxification and also their potential role in the

Financial support from FCT/MCTES through national funds UID/

Commission (CCDR-N)/NORTE2020/Portugal 2020 (Norte-01-0145-

MULTI/04378/2019 and Norte Portugal Regional Coordination and Development

FEDER-000024) and a PhD grant (SRRH/BD/139622/2018) attributed to D. Melo.

from the metabolic stress of long-term erythrocyte storage [93, 97].

membrane and counteract the effects of OS.

**76**
