scholarly journals Intracellular enzymes of collagen biosynthesis in rat liver as a function of age and in hepatic injury induced by dimethylnitrosamine. Changes in prolyl hydroxylase, lysyl hydroxylase, collagen galactosyltransferase and collagen glucosyltransferase activities

1976 ◽  
Vol 158 (2) ◽  
pp. 361-367 ◽  
Author(s):  
J Risteli ◽  
K I Kivirikko
Keyword(s):  
Rat Liver ◽  
Enzyme Activities ◽  
Hepatic Injury ◽  
Prolyl Hydroxylase ◽  
Collagen Biosynthesis ◽  
Hydroxylase Activity ◽  
Post Translational Modifications ◽  
Lysyl Hydroxylase ◽  
Intracellular Enzymes ◽  
The Relationship

The relationship between the changes in the four enzyme activities catalysing intracellular post-translational modifications in collagen biosynthesis were studied in rat liver as a function of age and in experimental hepatic injury induced by the administration of dimethylnitrosamine. During aging, relatively large changes were found in prolyl hydroxylase and lysyl hydroxylase activities, whereas only minor changes took place in collagen galactosyltransferase and collagen glucosyltransferase activities. In hepatic injury, the two hydroxylase activities increased earlier and to a larger extent than did the two glycosyltransferase activities, and the largest was found in lysyl hydroxylase activity. The data support previous suggestions that changes in the rate of collagen biosynthesis in the liver cannot be explained simply by a change in the number of collagen-producing cells, but regulation of the enzyme activities existed, so that the two hydroxylase activities altered considerably more than did the two collagen glycosyltransferase activities.

scholarly journals Intracellular enzymes of collagen biosynthesis in rat liver as a function of age and in hepatic injury induced by dimethylnitrosamine. Purification of rat prolyl hydroxylase and comparison of changes in prolyl hydroxylase activity with changes in immunoreactive prolyl hydroxylase

1976 ◽  
Vol 158 (2) ◽  
pp. 369-376 ◽  
Author(s):  
J Risteli ◽  
L Tuderman ◽  
K I Kivirikko
Keyword(s):  
Enzyme Activity ◽  
Rat Liver ◽  
Hepatic Injury ◽  
Specific Activity ◽  
Prolyl Hydroxylase ◽  
Newborn Rats ◽  
Hydroxylase Activity ◽  
Immunoreactive Protein ◽  
Molecular Weights ◽  
Polypeptide Chains

Prolyl hydroxylase was purified from newborn rats by affinity chromatography using poly(L-proline), and antiserum to the enzyme was prepared in rabbits. The rat prolyl hydroxylase was similar to the chick and human enzymes with respect to specific activity, molecular weight and molecular weights of the polypeptide chains. The activity of prolyl hydroxylase and the content of immunoreactive enzyme were measured in rat liver as a function of age in experimental hepatic injury. Active prolyl hydroxylase comprised about 13.2% of the total immunoreactive protein in the liver of newborn rats and the value decreased to about 3.6% at the age of 420 days. This decrease was due to a decrease in the enzyme activity, whereas only minor changes were found in the content of the immunoreactive protein. In hepatic injury, a significant increase was found in the ratio of active enzyme to total immunoreactive protein, owing to an increase in the enzyme activity. The data indicate that prolyl hydroxylase activity in rat liver is controlled in part by a mechanism which does not involve changes in the content of the total immunoreactive protein.

scholarly journals Effect of cortisol acetate on collagen biosynthesis and on the activities of prolyl hydroxylase, lysyl hydroxylase, collagen galactosyltransferase and collagen glucosyltransferase in chick-embryo tendon cells

1977 ◽  
Vol 164 (3) ◽  
pp. 533-539 ◽  
Author(s):  
A Oikarinen
Keyword(s):  
Chick Embryo ◽  
Enzyme Activities ◽  
Collagen Synthesis ◽  
Enzyme Synthesis ◽  
Prolyl Hydroxylase ◽  
Chick Embryos ◽  
Isolated Cells ◽  
Lysyl Hydroxylase ◽  
Tendon Cells

Collagen synthesis and the activities of prolyl hydroxylase, lysyl hydroxylase, collagen galactosyltransferase and collagen glucosyltransferase were studied in isolated chick-embryo tendon cells after the administration of cortisol acetate to the chick embryos. When the steroid was injected 1 day before isolation of the tendon cells, collagen synthesis was decreased, even though the enzyme activities were not changed. When cortisol acetate was given as repeated injections over a period of 4 days, both collagen synthesis and the enzyme activities decreased. The hydroxylase activities decreased even more than the two collagen glycosyltransferase activities, both in isolated cells and in whole chick embryos. The amount of prolyl hydroxylase protein diminished to the same extent as the enzyme activity, indicating that cortisol acetate inhibits enzyme synthesis. The inhibitory effect of cortisol acetate on collagen synthesis and on the enzyme activities was partially reversible in 3 days. Total protein synthesis was completely restored within this time. Only massive doses of cortisol acetate inhibited collagen synthesis in vitro. Additional experiments indicated that cortisol acetate did not decrease the rate of the enzyme reactions when added directly to the enzyme incubation mixtures. The results suggest that cortisol acetate decreases collagen synthesis both by its direct effect on collagen polypeptide-chain synthesis and by decreasing the activities of enzymes involved in post-translational modifications.

Increase in lipoperoxides and prolyl hydroxylase activity in rat liver following chronic ethanol feeding

1990 ◽  
Vol 40 (5) ◽  
pp. 1015-1019 ◽  
Author(s):  
Yamada Sadako ◽  
Yamada Minoru ◽  
Murawaki Yoshikazu ◽  
Hirayama Chisato
Keyword(s):  
Rat Liver ◽  
Prolyl Hydroxylase ◽  
Chronic Ethanol ◽  
Hydroxylase Activity ◽  
Ethanol Feeding

scholarly journals Activities of prolyl hydroxylase, lysyl hydroxylase, collagen galactosyltransferase and collagen glucosyltransferase in the liver of rats with hepatic injury

1974 ◽  
Vol 144 (1) ◽  
pp. 115-122 ◽  
Author(s):  
Juha Risteli ◽  
Kari I. Kivirikko
Keyword(s):  
Carbon Tetrachloride ◽  
Enzyme Activities ◽  
Hepatic Injury ◽  
Activity Patterns ◽  
Collagen Content ◽  
Lysyl Hydroxylase ◽  
Carbon Tetrachloride Administration ◽  
Liver Homogenates ◽  
Triton X ◽  
Polypeptide Chains

The activities of four enzymes catalysing post-translational modifications of the collagen polypeptide chains were assayed in the livers of rats with experimental hepatic injury. The liver injury was induced by injecting carbon tetrachloride twice weekly, and assays of the enzymic activities were carried out 2 and 4 weeks after commencement of administration of carbon tetrachloride. The liver homogenates were preincubated with Triton X-100 before the assays, because such treatment was found to increase the activities of all four enzymes in the supernatants of liver homogenates. The activities of all four enzymes had increased by 2 weeks after commencement of carbon tetrachloride administration. No increase was found in the collagen content of the livers at this stage and thus an increase in all four enzyme activities preceded an increase in the collagen content of the liver. A further slight increase was found in three of the enzyme activities during the subsequent 2 weeks of the experiment, whereas no further increase was found in the collagen galactosyltransferase activity. A statistically significant correlation was found between all four enzyme activities, but the magnitude of the increases varied considerably. The largest increase was found in lysyl hydroxylase activity, and at 4 weeks the magnitude of this was about three times that of the collagen galactosyltransferase activity. The results thus indicate that the increased enzyme activities cannot be explained simply by an increase in the number of collagen-producing cells having similar enzyme activity patterns to those of the cells initially present in the liver.

scholarly journals Intracellular enzymes of collagen biosynthesis in human platelets

Blood ◽  
1977 ◽  
Vol 50 (1) ◽  
pp. 29-37
Author(s):  
H Anttinen ◽  
L Tuderman ◽  
A Oikarinen ◽  
KI Kivirikko
Keyword(s):  
Enzyme Inhibitor ◽  
Relative Activity ◽  
Human Platelets ◽  
Prolyl Hydroxylase ◽  
Skin Extract ◽  
Collagen Biosynthesis ◽  
Substrate Complex ◽  
Enzyme Substrate ◽  
Intracellular Enzymes ◽  
Native Collagen

Activities of four intracellular enzymes of collagen biosynthesis-- prolyl hydroxylase, lysyl hydroxylase, collagen galactosyltransferase, and collagen glucosyltransferase--were demonstrated in human platelets, and the presence of prolyl hydroxylase protein was further demonstrated by direct radioimmunoassay. The ratio of the specific activities of the four enzymes in the four enzymes in the human platelet extract to those in human adult skin extract varied from about 0.1 to 1, the lowest relative activity being found with prolyl hydroxylase and the highest with collagen glucosyltransferase. Only a very small amount of prolyl hydroxylase protein, probably 1%, was in the form of the active enzyme tetramer. The collagen glucosyltransferase from human platelets readily glucosylated galactosylhydroxylysine in denatured collagen, but did not glucosylate native collagen. Also, native collagen did not act as an inhibitor of the glucosylation reaction. Therefore, platelet collagen glucosyltransferase cannot form either an enzyme--substrate complex or an enzyme--inhibitor complex with native collagen. The results thus argue against the theory which maintains that platelet collagen glucosyltransferase is involved in collagen--platelet adhesion.

scholarly journals Studies on enzymes of collagen biosynthesis and the synthesis of hydroxyproline in macrophages and mast cells

1979 ◽  
Vol 182 (2) ◽  
pp. 311-316 ◽  
Author(s):  
Raili Myllylä ◽  
Heikki Seppä
Keyword(s):  
Mast Cells ◽  
Enzyme Activities ◽  
Peritoneal Macrophages ◽  
Cell Extract ◽  
Cell Protein ◽  
Collagen Biosynthesis ◽  
Intracellular Enzyme ◽  
Lysyl Hydroxylase ◽  
Soluble Cell ◽  
Tendon Cells

The activities of four intracellular enzymes of collagen biosynthesis were assayed in freshly isolated rat peritoneal macrophages and mast cells and compared with the same enzymes in freshly isolated chick-embryo tendon cells. The macrophages were found to contain activities of all four enzymes, those of prolyl and lysyl hydroxylase being 7 and 12% respectively of those in the tendon cells when expressed per cell or 3 and 4% when expressed per unit of soluble cell protein. The corresponding values for hydroxylysyl galactosyltransferase and galactosylhydroxylysyl glucosyltransferase activities were about 82 and 68% or 32 and 24% respectively. When the macrophages were incubated in suspension with [14C]proline, they synthesized a small but significant amount of non-diffusible hydroxy[14C]proline. The synthesis per cell was only about 0.1% of that formed by the tendon cells, and its distribution between the cells and the medium also differed from that in the tendon cells. The hydroxy[14C]proline synthesized by the macrophages may be present in the Clq subcomponent of the complement, but its amount was too small to allow any characterization of the protein. All four enzyme activities, and in particular the two hydroxylysyl glycosyltransferase activities, seem to be present in macrophages in a large excess compared with the very low rate of synthesis of hydroxy-proline-containing polypeptide chains. The mast cell extract was found to inhibit all four enzyme activities, but even when corrected for this inhibition, prolyl and lysyl hydroxylase activities in the mast cells were less than 0.08% and the two hydroxylysyl glycosyltransferase activities less than 1% of those in the tendon cells. The intracellular enzyme pattern of collagen biosynthesis in the mast cells is thus completely or virtually completely repressed.

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