Incorporation of [14C] glucosamine and [14C] leucine into mouse kidney beta-glucuronidase induced by gonadotrophin.
Male BALB/C mice were injected intraperitoneally with 2.5 i.u. of gonadotrophin. After the injection, increase of beta-glucuronidase activity was first observed in the microsomal fraction. By 36h 45-50% of the total homogenate activity was found in the microsomal fraction compared with 20-25% in the control microsomal fraction. From 36 to 80h not only microsomal beta-glucuronidase but also lysosomal beta-glucuronidase increased progressively. After 69h stimulation with 2.5 i.u. of gonadotrophin, d-[1-(14)C]glucosamine or l-[U-(14)C]leucine was injected intraperitoneally. After a further 3h the kidneys were homogenized and five particulate fractions were prepared by differential centrifugation. The beta-glucuronidase in the microsomal and lysosomal fractions was released respectively by ultrasonication and by freezing and thawing treatment. The enzyme was purified by organic-solvent precipitation and by sucrose-density-gradient centrifugation. The results demonstrated the incorporation of these two labels into the mouse renal beta-glucuronidase. The microsomal beta-glucuronidase was much more radioactive than the lysosomal enzyme and approx. 80% of the newly synthesized enzyme appeared in microsomes and approx. 20% of that was found in lysosomes at this period. These results suggest that the mouse renal beta-glucuronidase is a glycoprotein and that the newly synthesized enzyme is transported from endoplasmic reticulum to lysosomes.
D000818:Animals; D001692:Biological Transport; D002247:Carbon Isotopes; D002499:Centrifugation, Density Gradient; D004721:Endoplasmic Reticulum; D004790:Enzyme Induction; D005615:Freezing; D005944:Glucosamine / Q000378:metabolism*; D005966:Glucuronidase / Q000096:biosynthesis* / Q000302:isolation & purification; D006023:Glycoproteins; D006062:Gonadotropins / Q000494:pharmacology*; D007274:Injections, Intraperitoneal; D007668:Kidney / Q000187:drug effects / Q000201:enzymology*; D007930:Leucine / Q000378:metabolism*; D008247:Lysosomes / Q000201:enzymology; D008297:Male; D051379:Mice; D008861:Microsomes / Q000201:enzymology; D013268:Stimulation, Chemical; D013997:Time Factors; D014465:Ultrasonics
D002247:Carbon Isotopes; D006023:Glycoproteins; D006062:Gonadotropins; D005966:Glucuronidase; D007930:Leucine; D005944:Glucosamine