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MAXIMUM ACTIVITIES, PROPERTIES AND DISTRIBUTION OF 5’NUCLEOTIDASE, ADENOSINE KINASE AND ADENOSINE DEAMINASE IN RAT AND HUMAN BRAIN
Author(s) -
Phillips E.,
Newsholme E. A.
Publication year - 1979
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1979.tb05187.x
Subject(s) - 5' nucleotidase , adenosine deaminase , adenosine , amp deaminase , nucleotidase , adenosine kinase , human brain , biochemistry , enzyme , biology , adenosine a2b receptor , chemistry , neuroscience , adenosine receptor , receptor , agonist
— The maximum activities of 5’nucleotidase, adenosine kinase and adenosine deaminase have been measured in several areas of rat and human brain. There is no major difference between the activities of nucleotidase and kinase between rat and human brain, but the activity of deaminase is considerably higher in human brain. The activities of all these enzymes are similar in three areas of rat brain and nine areas of human brain, except for hind brain of the human, which has a low activity of adenosine deaminase. This variation may indicate the existence of different steady‐state concentrations of adenosine in certain areas of the brain. Subcellular fractionation of different areas of rat brain showed that, whereas adenosine kinase and deaminase activities were located mainly in the soluble fractions, 5’nucleotidase was present in all subcellular fractions (i.e. membrane, synaptosomal, mitochondrial and soluble). In particular, there was no major localisation within the synaptosomal fraction. Thus it is unlikely that the regulation of the activities of these enzymes is dependent upon changes within a specific compartment (e.g. synaptosomes) in the brain.