Enhanced activity of pyrimidine 5'-nucleotidase in rat red blood cells during erythropoiesis.
A nucleotidase that catalyzed selective hydrolysis of pyrimidine 5'-nucleotides was investigated in rat red blood cells (RBCs). The enzyme had similar catalytic properties to human pyrimidine 5'-nucleotidase I (P5N-I). The P5N-I deficiency was known to be closely correlated with the human inherited disease, non-spherocytic hemolytic anemia. Similar to the human P5N-I, the rat enzyme preferentially hydrolyzed 5'-(d)CMP and 5'-UMP but no reactivity was observed with any 3'-nucleotide. Molecular mass of the enzyme was estimated to be approximately 38 kDa by gel filtration and SDS-polyacrylamide gel electrophoresis. Another subclass of pyrimidine 5'-nucleotidase, P5N-II, was also present in rat RBCs. This P5N-II-like enzyme, which resembled a 5'(3')-nucleotidase, preferentially hydrolyzed both 5'- and 3'- of (d)TMP or (d)UMP, but no cytosine nucleotide was hydrolyzed by the enzyme. Results from the reactivity with the antibody against rat 5'(3')-nucleotidase and estimated subunit molecular mass of the enzymes, about 26 kDa, suggested that the P5N-II-like enzyme had a similar structure to the 5'(3')-nucleotidase. The P5N-I-like activity in rat RBCs increased 5 to 6-fold at 4 days after phenylhydrazine injection, and reached a maximum at 6 to 7 days. No change in the activity of P5N-II-like nucleotidase was observed during the experimental period. The increase in rat P5N-I activity coincided with maturation of the erythrocytes.
Hokari
S
S
Department of Biochemistry, Saitama Medical School, Japan.
Miyazaki
T
T
Hasegawa
M
M
Komoda
T
T
D015720:5'-Nucleotidase / Q000097:blood*; D000818:Animals; D003568:Cytidine Monophosphate / Q000378:metabolism; D004912:Erythrocytes / Q000201:enzymology*; D004920:Erythropoiesis; D006801:Humans; D006868:Hydrolysis; D008297:Male; D008970:Molecular Weight; D051381:Rats; D017208:Rats, Wistar; D013154:Spleen / Q000502:physiology; D013379:Substrate Specificity
D015720:5'-Nucleotidase; D003568:Cytidine Monophosphate