Cytosolic 5¢-nucleotidase (cN-II), which acts preferentially on 6-hydroxypu-rine nucleotides, is essential for the survival of several cell types. cN-II
catalyses both the hydrolysis of nucleotides and transfer of their phosphate
moiety to a nucleoside acceptor through formation of a covalent phospho-intermediate.
Cytosolic 5¢-nucleotidase/phosphotransferase specific for
6-hydroxypurine monophosphate derivatives (cN-II),
belongs to a class of phosphohydrolases that act through the
formation of an enzyme–phosphate intermediate. Sequence
alignment with members of the P-type ATPases/L-2-halo-acid dehalogenase superfamily identified three highly con-served motifs in cN-II and other cytosolic nucleotidases.
Mutagenesis studies at specific amino acids occurring in
Trao đổi nucleic acid
12.1. Sự phân giải nucleic acid
12.1.1. Thủy phân nucleic acid Sự thủy phân nucleic acid thành mononucleotide được xúc tác bởi các enzmie thủy phân tương ứng. DNA nhờ desoxyribonuclease xúc tác biến đổi thành các desoxyribonucleotide còn RNA do các ribonuclease xúc tác sẽ bị phân giải thành các ribonucleotide. 12.1.2. Phân giải mononucleotide Mononucleotide bị phân giải bởi tác dụng của các phosphatase hoặc nucleotidase tạo nên các nucleoside và H3PO4.
Pyrimidine 5'-Nucleotidase (P5N) Deficiency P5N is a key enzyme in the catabolism of nucleotides arising from the degradation of nucleic acids that takes place in the final stages of red cell maturation. How exactly its deficiency causes HA is not well understood, but a highly distinctive feature of this condition is a morphologic abnormality of the red cells known as basophilic stippling. The condition is rare, but it probably ranks third in frequency among red cell enzyme defects (after G6PD deficiency and PK deficiency).
The genome data of bacteriumXylella fastidiosastrain 9a5c has identified
severalorfsrelated to its phytopathogenic adaptation and survival. Among
these genes, the surEcodifies a survival protein E (XfSurE) whose function
is not so well understood, but functional assays in Escherichia colirevealed
nucleotidase and exopolyphosphate activity.