<prompt> In RBC the enzyme deficient isHexokinasePhosphofructokinasePyruvate kinaseGlycerol kinase  <response>: Pyruvate kinase is an enzyme that helps Cells turn sugarglucose into energy Called Adenosine Triphsphate,ATP in a process called glycolysis . Red cells rely on this process for energy and so, pyruvate kinase deficiency leads to a deficiency in energy and to premature red cell destruction . 