Galactose metabolism in regenerating rat liver

Abstract

1. Rats trained on a controlled lighting and feeding schedule were subjected to partial hepatectomy or sham operation. 2. After a large period of about 6h the activity of UDP-galactose 4-epimerase increased threefold, reaching a maximum 4 days after partial hepatectomy, and returned to normal values within a fortnight. 3. The enzyme pattern of the UDP-galactose-glycoprotein galactosyltransferase was biphasic, one peak appearing at 20 h, the second at 72 h after partial hepatectomy. 4. The rise in enzyme activities could be blocked by the injection of actinomycin D, and the Km values for UDP-glucose and UDP-galactose were nearly identical in regenerating and adult liver. It is therefore concluded that the increase in enzyme activity is due to synthesis de novo of enzyme protein.

Subcellular localization of the enzyme that forms mannosyl retinyl phosphate from guanosine diphosphate [14C]mannose and retinyl phosphate

“…(c) 5'-Nucleotidase as plasma-membrane marker (Aronson &Touster, 1974), with the modification of using 0.2ml of 2.48% ascorbate instead of 1-amino-2-naphthol-4-sulphonic acid for phosphorus assay. (d) Galactosyl transferase as Golgi-apparatus marker (Mookerjea & Yung, 1975;Bauer et al, 1976). (e) RNA assays (Munro & Fleck, 1966 Fig.…”

“…1. In addition, the Golgi apparatus marker enzyme, galactosyltransferase (Morre, 1969;Mookerjea & Yung, 1975;Bauer et al, 1976) terminated by the addition of 3 ml of chloroform/ methanol (2:1, v/v), followed by 0.6ml of 0.9% NaCl. The mixture was shaken on a vortex mixer, the lower (organic) phase was removed (first extract) and washed twice with 0.4 ml of 0.9 % NaCI/methanol (2: 1, v/v).…”

Ganglioside biosynthesis in rat liver. Characterization of UDPgalactose- glucosylceramide galactosyltransferase and UDPgalactose-GM2 galactosyltransferase

“…UDP-Galglycoprotein galactosyltransferase was assayed according to Bauer et al [12], its activity was used to calculate the enrichment of Golgi-associated protein in the Golgi-rich membrane fraction. In a total volume of 120 pl, 6 pmol sodium cacodylate, pH 6.75, 1.2 pmol MnCI,, 0.2 pmol dithioerythritol, 0.1 5 pmol UDP-[U-'4C]Gal, 0.5 (v/v) Triton X-100, and 0.6 mg desialo-degalacto-fetoprotein were incubated at 30 C for 30 min with either 75 -300 pg of homogenate protein or 2.5 -150 pg Golgi-associated protein.…”

Matrix Restructuring During Liver Regeneration is Regulated by Glycosylation of the Matrix Glycoprotein Vitronectin

“…ECM degradation occurs in the early stage of this process, followed by biosynthesis of the matrix, cell proliferation, and cell differentiation. During this process, many glycosyl transferases (Bauer, C.H., et al 1976;Serafini-Cessi, F. 1977;Okamoto, Y., et www.intechopen.com Liver Regeneration 80 al. 1978;Ip, C. 1979;Oda-Tamai, S., et al 1985;Miyoshi, E., et al 1995) and total glycoconjugates in the liver have been reported to change (Okamoto, Y. and Akamatsu, N. 1977;Kato, S. and Akamatsu, N. 1984;Kato, S. and Akamatsu, N. 1985;Ishii, I., et al 1985).…”