Human Adenine Phosphoribosyltransferase
نویسنده
چکیده
Human adenine phosphoribosyltransferase has been purified 33,000-fold from erythrocytes to a specific activity of 9.58 pmoles of AMP formed per mg of protein per min. The native enzyme has a molecular weight of 34,000 and is composed of three subunits of equal molecular weight which appear to be associated by noncovalent forces. The highly purified enzyme is maximally active over a broad pH range from 7.4 to 9.5 and has an isoelectric point of 4.78. The compounds 4-amino-5-imidazolecarboxamide and 2,6-diaminopurine were found to be substrates for the highly purified enzyme. At 0’ in the absence of Mg++ but in the presence of substrates the human enzyme catalyzed a rapid and limited synthesis of AMP.
منابع مشابه
Assignment of the gene for adenine phosphoribosyltransferase to human chromosome 16 by mouse-human somatic cell hybridization.
A series of mouse-human hybrids was prepared from mouse cells deficient in adenine phosphoribosyltransferase (EC 2.4.2.7) and normal human cells. The hybrids were made in medium containing adenine and alanosine, an antimetabolite known to inhibit de novo adenylic acid biosynthesis. The mouse cells, unable to utilize exogenous adenine, were killed in this medium, but the hybrids proliferated as ...
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