Enzymatic Conversion of RBCs by α-N-Acetylgalactosaminidase from Spirosoma linguale.

Thomas J. Malinski,Harkewal Singh

doi:10.1155/2019/6972835

Abstract

Spirosoma linguale is a free-living nonpathogenic organism. Like many other bacteria, S. linguale produces a cell-associated α-N-acetylgalactosaminidase. This work was undertaken to elucidate the nature of this activity. The recombinant enzyme was produced, purified, and examined for biochemical attributes. The purified enzyme was ~50 kDa active as a homodimer in solution. It catalyzed hydrolysis of α-N-acetylgalactosamine at pH 7. Calculated KM was 1.1 mM with kcat of 173 s−1. The described enzyme belongs to the GH109 family.

Highlights

Substantial effort has been placed on stabilizing the worldwide blood supply
Two α-NAGAs that demonstrated conversion of Type A2 red blood cells (RBCs) to blood group O originated from chicken [17] and C. perfringens [13]
On Day 0, rabbits were bled for baseline antibodies and immunized with the test antigens in CFA

Summary

Introduction

Substantial effort has been placed on stabilizing the worldwide blood supply. It is commonplace to see appeals for blood donations because of low levels of supply. Each strategy has merit but they are not so without their technical challenges All of these approaches in concert may eventually play a role in stabilizing the blood supply. Several research groups have identified a number of enzymes that have the potential to convert RBC blood type. The enzymes targeted to amend the RBC to Type O are α-N-acetylgalactosaminidase (A󳨀→O) and αgalactosidase (B󳨀→O). The emphasis of this research involves enzymatically converting Type A RBC to O with a recombinant α-NAGA originating from Spirosoma linguale. The ABO blood group as described by Landsteiner [1] and characterized by Kabat, Watkins, and Morgan [2, 3] is rich in specific glycoconjugates targeted by α-NAGA. Individuals with type A blood group express Antigen A and antibody to Antigen B. Individuals with type B blood group express Antigen B and antibody to Antigen A. Individuals with A antigen produce antibodies to type B blood and vice versa and blood transfusions between incompatible blood types leads to immune response and can be fatal

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Conclusion