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Electrophoretic and kinetic studies of a mutant red cell pyrimidine 5'-nucleotidase
Abstract:
Human red cell pyrimidine 5'-nucleotidase (P5N) was studied by partial purification and condensation in a patient with an extremely low red cell P5N activity and chronic hemolytic anemia. The residual P5N in the red cell of the patient was characterized by an increased Michaelis constant for cytidine 5'-monophosphate, a marked shift of the pH optimum to the acidic side, normal electrophoretic mobility and normal heat stability. These data indicate that, in this patient, severe enzyme deficiency is caused by a structural gene mutation. This variant is clearly distinguished from a previously reported case and it is designated P5N Kagoshima.
Insights
This study investigated human red cell pyrimidine 5'-nucleotidase (P5N) deficiency in a patient with hemolytic anemia. The findings suggest a structural gene mutation causes this specific P5N Kagoshima variant.
Area of Science:
- Biochemistry
- Genetics
- Hematology
Background:
- Pyrimidine 5 -nucleotidase (P5N) is crucial for red blood cell metabolism.
- Deficiency in P5N activity is linked to chronic hemolytic anemia.
- Understanding enzyme variants aids in diagnosing and managing genetic blood disorders.
Observation:
- A patient presented with extremely low red cell P5N activity and chronic hemolytic anemia.
- Partial purification and characterization of the residual P5N enzyme were performed.
- Key kinetic and stability properties of the patient's P5N were analyzed.
Findings:
- The patient's P5N exhibited an increased Michaelis constant for cytidine 5 -monophosphate.
- A significant shift in the pH optimum towards the acidic range was observed.
- Electrophoretic mobility and heat stability remained normal, distinguishing it from other variants.
Implications:
- The observed characteristics strongly indicate a structural gene mutation responsible for the severe enzyme deficiency.
- This specific variant, designated P5N Kagoshima, is distinct from previously identified cases.
- Characterizing novel enzyme variants contributes to the understanding of genetic metabolic diseases.