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.

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.

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 Wachstumsgeschwindigkeit der Peptidkette im Tabakmosaikvirus

1967 ◽  
Vol 22 (12) ◽  
pp. 1280-1291 ◽  
Author(s):  
H. Diringer ◽  
F. A. Anderer ◽  
G. Schramm
Keyword(s):  
Amino Acids ◽  
Growth Rate ◽  
Protein Synthesis ◽  
Peptide Chain ◽  
Cell Protein ◽  
Virus Protein ◽  
Animal Cells ◽  
Tobacco Leaves ◽  
Soluble Cell ◽  
C Terminus

The rate of incorporation of labelled amino acids into the complete tobacco mosaic virus (TMV), into soluble virus protein and into soluble cell proteins has been determined in discs of infected and healthy tobacco leaves. The rate of overall protein synthesis is increased by 50% in the infected leaves. At least 60% of the increase derives from the synthesis of virus-specific proteins and the synthesis of cellular proteins is not inhibited. The virus protein synthesis is strongly temperature dependent and shows a maximum at 28 °C.The exchange of free labelled amino acids between the external medium and the inner cellular pool reaches equilibrium within ten minutes. The influence of the exchange rate on the measurement of the kinetics of peptide chain synthesis is discussed in detail.Discs from infected leaves were incubated for short periods at low temperatures in media containing 3H-tyrosine or 3H-proline. Peptides isolated after 5 minutes incubation at 15 °C were found to be uniformly labelled with no apparent gradient of radioactivity from the N- to the C-terminus. The results indicate that the growth rate of the peptide chain at 15 °C is probably higher than 2 - 3 amino acids/sec and at 28 °C higher than 20 amino acids/sec. These values are higher than those for animal cells and similar to those for protein synthesis in Escherichia coli.Comparison of the growth rate of TMV protein with rate of total protein synthesis and the number of ribosomes in the tobacco leaves indicate that only a small portion of the ribosomes takes part in cell protein synthesis.

A Protein-bound Polysaccharide Synergistic with Lipopolysaccharide Induces Nitric Oxide Release and Antioxidant Enzyme Activities in Mouse Peritoneal Macrophages

1998 ◽  
Vol 26 (02) ◽  
pp. 133-141 ◽  
Author(s):  
Zhan-Jun Pang ◽  
Mei Zhou ◽  
Yuan Chen ◽  
Jennifer Wan
Keyword(s):  
Nitric Oxide ◽  
Enzyme Activities ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Peritoneal Macrophages ◽  
Treated Mouse ◽  
Antioxidant Enzyme Activities ◽  
Sod Activity ◽  
Nitric Oxide Release ◽  
Mouse Peritoneal Macrophages

The aim of this study is to examine whether polysaccharide krestin, a protein-bound polysaccharide, can prevent the progression of therosclerosis and lipoperoxidative injury caused by oxidatively modified low density lipoprotein (Ox-LDL) to macrophages. The alterations of GSHPx (glutathione peroxidase), SOD (superoxide dismutase) activity and NO (nitric oxide) release in PSK-treated mouse peritoneal macrophages, and the effect of LPS on them were investigated. With peritoneal injection of PSK, the following were observed in the mouse peritoneal macrophages: 1) an increase in SeGSHPx activity, 2) elevation in non-SeGSHPx and SOD activity; 3) the enzyme activities were further improved by addition of lipopolysaccharide (LPS); and 4) much NO was found to be released by PSK-treated mouse peritoneal macrophages stimulated by LPS.

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