scholarly journals Modification of the single sulfhydryl group of carboxypeptidase Y with mercurials. Influence on enzyme specificity

1983 ◽  
Vol 48 (1) ◽  
pp. 9-19 ◽  
Author(s):  
Klaus Breddam
Keyword(s):  
Sulfhydryl Group ◽  
Carboxypeptidase Y ◽  
Enzyme Specificity

Sulfhydryl bond formation is a prerequisite for proper cycling of centrosomes and chromosomes in mammalian tissue culture cells

1993 ◽  
Vol 51 ◽  
pp. 342-343
Author(s):  
Heide Schatten ◽  
Neidhard Paweletz ◽  
Ron Balczon
Keyword(s):  
Tissue Culture ◽  
Cell Cycle Progression ◽  
Group Formation ◽  
Sulfhydryl Group ◽  
Mammalian Tissue ◽  
Mitotic Chromosomes ◽  
Microtubule Network ◽  
Culture Cells ◽  
Tissue Culture Cells ◽  
Transmission Electron

To study the role of sulfhydryl group formation during cell cycle progression, mammalian tissue culture cells (PTK2) were exposed to 100¼M 2-mercaptoethanol for 2 to 6 h during their exponential phase of growth. The effects of 2-mercaptoethanol on centrosomes, chromosomes, microtubules, membranes and intermediate filaments were analyzed by transmission electron microscopy (TEM) and by immunofluorescence microscopy (IFM) methods using a human autoimmune antibody directed against centrosomes (SPJ), and a mouse monoclonal antibody directed against tubulin (E7). Chromosomes were affected most by this treatment: premature chromosome condensation was detected in interphase nuclei, and the structure in mitotic chromosomes was altered compared to control cells. This would support previous findings in dividing sea urchin cells in which chromosomes are arrested at metaphase while the centrosome splitting cycle continues. It might also support findings that certairt-sulfhydryl-blocking agents block cyclin destruction. The organization of the microtubule network was scattered probably due to a looser organization of centrosomal material at the interphase centers and at the mitotic poles.

Human Neuraminidases Have Reduced Activity Towards Modified Sialic Acids on Glycoproteins

2020 ◽  
Author(s):  
Carmanah D. Hunter ◽  
Elizabeth Porter ◽  
Christopher Cairo
Keyword(s):  
Substrate Specificity ◽  
General Trend ◽  
Sialic Acids ◽  
Enzyme Specificity ◽  
Naturally Occurring ◽  
Bovine Submaxillary Mucin ◽  
Reduced Activity

This work investigated the substrate specificity of hNEU enzymes for a glycoprotein substrate (bovine submaxillary mucin) containing 9-<i>O</i>-acetylated and Neu5Gc residues. Using this model substrate, we observe a general trend for hNEU tolerance of Neu5Ac>Neu5Gc>>>Neu5,9Ac<sub>2</sub>, consistent with our previous results with glycolipid substrates. These results expand our understanding of hNEU enzyme specificity and suggest that naturally occurring modifications of sialic acids can play a role in regulating hNEU activity.

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