Alterations in tyrosine aminotransferase isoenzymes of liver of rats as a function of age.
The specific activities (units/mg protein) of tyrosine aminotransferase (TAT) and its isoenzymes, cytoplasmic (c-), mitochondrial (m-) and nuclear (n-TAT), of the liver of 6-, 35- and 76-week old male albino rats were determined. The activities of all the isoenzymes are highest at 6 weeks and are significantly lower at 35 weeks. Total TAT and c-TAT remain unchanged, m-TAT decreases and n-TAT increases significantly after 35 weeks. c-TAT was partially purified from the liver of rats of the three ages to study its kinetic and molecular properties. These properties apparently do not change as a function of age.
D000367:Age Factors; D000818:Animals; D002467:Cell Nucleus / Q000201:enzymology; D003593:Cytoplasm / Q000201:enzymology; D005971:Glutamates / Q000378:metabolism; D007527:Isoenzymes / Q000378:metabolism*; D007656:Ketoglutaric Acids / Q000378:metabolism; D007700:Kinetics; D008099:Liver / Q000201:enzymology*; D008297:Male; D008930:Mitochondria, Liver / Q000201:enzymology; D051381:Rats; D014443:Tyrosine / Q000378:metabolism; D014444:Tyrosine Transaminase / Q000378:metabolism*
D005971:Glutamates; D007527:Isoenzymes; D007656:Ketoglutaric Acids; D014443:Tyrosine; D014444:Tyrosine Transaminase