Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Pivot Concepts:
Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Target Concepts:
Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Query: EC:3.1.3.5 (
5'-nucleotidase
)
3,167
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
Evidence is presented for a direct interaction of the intrinsic membrane protein
5'-nucleotidase
(
5'-ribonucleotide phosphohydrolase
,
EC 3.1.3.5
) purified from avian smooth muscle (chicken gizzard) and the cytoskeletal component actin. Two different modes of interaction can be discerned: firstly, an immediate inhibitory effect of preferentially filamentous actin (F-actin) on the enzymic (i.e.,
AMPase
) activity of
5'-nucleotidase
and a direct binding of this enzyme to immobilized F-actin. Since these effects are suppressed by the addition of myosin subfragment 1, binding of
5'-nucleotidase
appears to occur along the F-actin filament axis. Secondly, a time- and
5'-nucleotidase
concentration-dependent transformation of also preferentially F-actin into a form unable to inhibit the enzymic activity of
deoxyribonuclease I
(DNAase I). This desensitization of actin versus DNAase I is not due to a denaturation process and was found to be reversible after addition of ATP. Furthermore, it does not seem to effect the ability of actin to bind to DNAase I. The transformation is accompanied by the hydrolysis of actin-bound nucleotide into adenosine, which remains bound to actin. Therefore, the desensitization of actin versus DNAase I appears to be due to a nucleotide-dependent conformational change of actin. An unidentified contamination of the
5'-nucleotidase
preparations to a varying degree with ADPase and ATPase activities appears to be responsible for the desensitization process, although a synergistic role of these activities and
5'-nucleotidase
cannot be excluded.
...
PMID:The interaction of 5'-nucleotidase purified from chicken gizzard and actin, and the reversible loss of the inhibitory capacity of actin on deoxyribonuclease I. 298
The transmembrane topography of the rat hepatocyte ectoenzyme
5'-nucleotidase
was studied by the use of glycoprotein labelling and limited-proteolysis techniques. Comparison, by one-dimensional peptide mapping, of enzyme iodinated from outside the cell with that iodinated in the solubilized state showed that no additional iodination sites were revealed on solubilization. Incubation of newly synthesized enzyme in a microsomal membrane fraction with proteinase showed that the entire molecule of
5'-nucleotidase
was protected from proteolysis. These data suggest that little, if any, of the
5'-nucleotidase
molecule is present on the cytoplasmic side of the plasma membrane. No evidence was found for a previously proposed interaction between
5'-nucleotidase
and actin, although the ability of preparations of
5'-nucleotidase
to prevent inhibition of
deoxyribonuclease I
by actin was explained by minute traces of ATPase activity. Comparison of peptide maps of enzyme labelled by iodination or by methods specific for carbohydrate showed that in both cases predominantly one section of the molecule was labelled. It is proposed that the enzyme is a short-stalked integral membrane protein without a cytoplasmic domain in which about one-third of the molecule forms the accessible molecular surface.
...
PMID:The membrane topography of ecto-5'-nucleotidase in rat hepatocytes. 301 17
