Role of the Primary Specificity Subsite on the Interaction between Serine Proteinases and Low Molecular Weight Substrates and Inhibitors

1987 ◽  
pp. 101-115 ◽  
Author(s):  
Enea Menegatti ◽  
Mario Guarneri ◽  
Martino Bolognesi ◽  
Paolo Ascenzi ◽  
Gino Amiconi
Keyword(s):  
Molecular Weight ◽  
Low Molecular Weight ◽  
Serine Proteinases ◽  
Primary Specificity

Polyamine metabolism and function

1982 ◽  
Vol 243 (5) ◽  
pp. C212-C221 ◽  
Author(s):  
A. E. Pegg ◽  
P. P. McCann
Keyword(s):  
Molecular Weight ◽  
Tissue Growth ◽  
Polyamine Metabolism ◽  
Organic Cations ◽  
Low Molecular Weight ◽  
Polyamine Biosynthesis ◽  
Polyamine Content ◽  
And Function ◽  
Specific Inhibitors

Polyamines are ubiquitous organic cations of low molecular weight. The content of these amines is closely regulated by the cell according to the state of growth. The reactions responsible for the biosynthesis and interconversion of the polyamines and their precursor putrescine are described and the means by which polyamine content can be varied in response to exogenous stimuli are discussed. The role of polyamines in the cell cycle, cell division, tissue growth, and differentiation is considered. Recent studies using highly specific inhibitors of polyamine biosynthesis such as alpha-difluoromethylornithine to prevent accumulation of polyamines have indicated that the synthesis of polyamines is intimately associated with these processes. Such inhibitors have great potential for investigation of the cellular role of polyamines.

scholarly journals Role of serum IgA. Hepatobiliary transport of circulating antigen.

1981 ◽  
Vol 153 (4) ◽  
pp. 968-976 ◽  
Author(s):  
M W Russell ◽  
T A Brown ◽  
J Mestecky
Keyword(s):  
Molecular Weight ◽  
Human Serum Albumin ◽  
Gel Filtration ◽  
Low Molecular Weight ◽  
Serum Iga ◽  
Circulating Antigen ◽  
Circulating Antigens ◽  
Iga Antibody ◽  
Immune Spleen Cell

The IgA mediated hepatobiliary excretion of antigen from the circulation was studied using a radiolabeled haptenated protein (dinitrophenyl-human serum albumin) injected intravenously in mice together with monoclonal anti-dinitrophenyl antibodies of different immunoglobulin classes. Antibodies were obtained from ascitic fluids of mice bearing the MOPC315 myeloma (IgA), or immune spleen cell hybridomas (IgG and IgM). IgA antibody brought about the transport of large amounts of antigen from the circulation to the bile during 1-3h. Analysis of bile by gel filtration showed that a large part of the transported antigen remained intact and complexed with IgA. Neither IgA of different specificity nor anti-dinitrophenyl IgM medicated biliary transport of antigen. With anti-dinitrophenyl IgG, only small amounts of low molecular weight fragments of labeled antigen were found in he bile. Preformed immune complex of radiolabeled antigen and IgA antibody were rapidly transported from the circulation to the bile, resulting in threefold-higher levels of radioactivity in bile than in serum. It is proposed that an important function of serum IgA is to mediate the hepatobiliary excretion of corresponding circulating antigens.

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