In vitro translocation of L-alanine:4,5-dioxovalerate transaminase into rat kidney mitochondria.
A specific rabbit antibody was prepared against rat kidney mitochondrial L-alanine: 4,5-dioxovalerate transaminase, which is one of the two enzymes catalyzing the synthesis of delta-aminolevulinic acid in the heme biosynthetic pathway. Total polyadenylated RNA isolated from rat kidney was translated in vitro using rabbit reticulocyte cell-free translation system, and L-alanine:4,5-dioxovalerate transaminase was estimated by indirect immunoprecipitation to represent 0.85% of the total translation product. When the total in vitro translated product was incubated with homologous kidney mitochondria, 59% of the [35S]methionine labeled enzyme was translocated into the mitochondria where it was no longer accessible to externally added protease. In relation to total protein translocation, the translocation of L-alanine:4,5-dioxovalerate transaminase remained unaltered by addition of hemin up to 50 microM. These results show that, unlike the other enzyme of the heme biosynthetic pathway (delta-aminolevulinic acid synthetase), this enzyme is not under tight control by heme, but nonetheless, functions as an important source to maintain a housekeeping level of delta-aminolevulinic acid.
Tyagi
R K
RK
Biochemistry Laboratory, School of Environmental Sciences, Jawaharlal Nehru University, New Delhi, India.
Datta
K
K
D000596:Amino Acids / Q000032:analysis; D000622:Aminolevulinic Acid / Q000378:metabolism*; D000818:Animals; D000911:Antibodies, Monoclonal; D000918:Antibody Specificity; D006427:Hemin / Q000494:pharmacology; D066298:In Vitro Techniques; D007668:Kidney / Q000378:metabolism* / Q000648:ultrastructure; D008928:Mitochondria / Q000378:metabolism*; D011061:Poly A / Q000235:genetics / Q000378:metabolism; D014176:Protein Biosynthesis; D012313:RNA / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger; D051381:Rats; D017208:Rats, Wistar; D000637:Transaminases / Q000737:chemistry / Q000276:immunology / Q000302:isolation & purification / Q000378:metabolism*
D000596:Amino Acids; D000911:Antibodies, Monoclonal; D012333:RNA, Messenger; D011061:Poly A; D012313:RNA; D006427:Hemin; D000622:Aminolevulinic Acid; D000637:Transaminases; C019687:aminolevulinate aminotransferase