scholarly journals A study of the role of metallothionein in the inherited copper toxicosis of dogs

1986 ◽  
Vol 236 (2) ◽  
pp. 409-415 ◽  
Author(s):  
D M Hunt ◽  
S A Wake ◽  
J F B Mercer ◽  
D M Danks

The role of metallothionein (MT) was assessed in the copper-loading disease prevalent in Bedlington terriers. Fractionation of tissue supernatants over Sephadex G-75 showed that most of the additional cytosolic copper present in liver tissue of these dogs was bound to MT, and that substantially more MT-bound copper could be solubilized by detergent plus mercaptoethanol. Zinc contents were only slightly raised, although most of the extra zinc was associated with a 4000-Mr ligand. Ion-exchange chromatography revealed two isoproteins, MT1 and MT2, in all the dog liver samples examined. In Bedlington terrier liver, copper associated with both isoproteins was increased, although the increase for MT2 was greater than for MT1. The content of MT protein was also raised, although cell-free translations and RNA blots of total liver RNA showed that this increase was not associated with a rise in MT mRNA. The significance of these results to the mechanism of copper accumulation in the Bedlington terrier disorder is discussed.

1968 ◽  
Vol 107 (1) ◽  
pp. 41-49 ◽  
Author(s):  
G. M. Herring

A fraction containing chondroitin sulphate, isolated from bovine cortical bone under mild conditions, was separated by ion-exchange chromatography into three fractions with apparent homogeneity on electrophoresis and ultracentrifugation. Two of these appeared to consist of chondroitin sulphate bound to a glycoprotein ‘core’ that had similarities to the bone sialoprotein described previously. The differences in composition of the two fractions were considered to be due to variation in the number or lengths of the polysaccharide chains. The presence of xylose and the alkali-lability of the bond between protein and polysaccharide suggested the presence of a xylosylserine linkage. The third fraction had the properties of a relatively pure chondroitin sulphate which contained a small amount of peptide. These fractions differed considerably from the protein–polysaccharide complexes of epiphysial and other cartilages, and their relevance to the possible role of glycosaminoglycans is discussed.


1973 ◽  
Vol 51 (6) ◽  
pp. 783-788 ◽  
Author(s):  
C. C. Yip ◽  
C. C. Liew

Slices of fetal bovine pancreas were used to study the initiation of proinsulin biosynthesis. The pancreatic slices were incubated with radioactive methionine, phenylalanine, or leucine, in a defined medium. The incorporation of amino acid into peptides in the tissue slices was measured for 2–3 h. Two types of radioactive peptides, "free" and "blocked," were identified by ion-exchange chromatography. Most of the radioactive "blocked" peptides labelled with [3H]phenylalanine and [35S]methionine were hydrolyzed by proteases, except for about 20% of those labelled with [35S]methionine, which also showed higher resistance to acid hydrolysis.Microsomes were isolated from the tissue slices after incubation and were extracted with acid alcohol. The radioactive proteins in the extract were reacted with a solid immunosorbant against insulin. Analysis of the immunoadsorbed radioactive peptides by Edman degradation showed the presence of both methionine and phenylalanine as the N-termini. It was concluded that methionine was an initiating amino acid in the biosynthesis of bovine proinsulin.


PLoS ONE ◽  
2010 ◽  
Vol 5 (11) ◽  
pp. e13948 ◽  
Author(s):  
Qiang Gao ◽  
Fabao Liu ◽  
Tongcun Zhang ◽  
Jian Zhang ◽  
Shiru Jia ◽  
...  

1973 ◽  
Vol 30 (02) ◽  
pp. 414-424 ◽  
Author(s):  
Ulla Hedner

SummaryA procedure is described for partial purification of an inhibitor of the activation of plasminogen by urokinase and streptokinase. The method involves specific adsorption of contammants, ion-exchange chromatography on DEAE-Sephadex, gel filtration on Sephadex G-200 and preparative electrophoresis. The inhibitor fraction contained no antiplasmin, no plasminogen, no α1-antitrypsin, no antithrombin-III and was shown not to be α2 M or inter-α-inhibitor. It contained traces of prothrombin and cerulo-plasmin. An antiserum against the inhibitor fraction capable of neutralising the inhibitor in serum was raised in rabbits.


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