Regulation of soluble 5'-nucleotidase I from rabbit heart.
Rabbit heart contains two soluble 5'-nucleotidases, termed N-I and N-II, which can be separated using phosphocellulose chromatography. N-I prefers AMP over IMP as substrate, in contrast to N-II which prefers IMP over AMP. Both enzymes require Mg2+, but the optimum Mg2+ concentrations for the two enzymes are different. High concentrations of NaCl inhibit N-I and activate N-II. Purified N-I is activated by ADP but not by ATP. According to Itoh et al. (1986), purified N-II is activated by both ADP and ATP. N-I has been purified approximately 1000-fold to a specific activity of approximately 100 mumol/mg protein/min. The properties of N-I suggest that it is the enzyme responsible for the release of adenosine from AMP under conditions of hypoxia or increased work load.
Yamazaki
Y
Y
Graduate Department of Biochemistry, Brandeis University Waltham, Massachusetts 02254.
Collinson
A R
AR
Truong
V L
VL
Lowenstein
J M
JM
D015720:5'-Nucleotidase / Q000302:isolation & purification* / Q000378:metabolism; D000244:Adenosine Diphosphate / Q000494:pharmacology; D000255:Adenosine Triphosphate / Q000494:pharmacology; D000818:Animals; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation / Q000187:drug effects; D015636:Magnesium Chloride / Q000494:pharmacology; D009206:Myocardium / Q000201:enzymology*; D011817:Rabbits; D012965:Sodium Chloride / Q000494:pharmacology; D013379:Substrate Specificity
D015636:Magnesium Chloride; D012965:Sodium Chloride; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D015720:5'-Nucleotidase