scholarly journals Streptococcus mutans Surface α-Enolase Binds Salivary Mucin MG2 and Human Plasminogen

2004 ◽  
Vol 72 (11) ◽  
pp. 6748-6752 ◽  
Author(s):  
Jingping Ge ◽  
Diana M. Catt ◽  
Richard L. Gregory
Keyword(s):  
Streptococcus Mutans ◽  
Mass Spectrometry Analysis ◽  
Enzyme Linked Immunosorbent Assay ◽  
Ionization Time ◽  
Spectrometry Analysis ◽  
Flight Mass Spectrometry ◽  
Salivary Mucin ◽  
Transmission Electron ◽  
A Cell ◽  
Human Plasminogen

ABSTRACT Matrix-assisted laser desorption ionization-time of flight mass spectrometry analysis identified enolase as a cell surface component of Streptococcus mutans, which was confirmed by enzyme-linked immunosorbent assay, Western blotting, and transmission electron microscopy. Surface enolase was demonstrated to bind to human plasminogen and salivary mucin MG2. The results suggested a role for enolase in S. mutans attachment, clearance, or breach of the bloodstream barrier.

scholarly journals Involvement of Two Cytosolic Enzymes and a Novel Intermediate, 5′-Oxoaverantin, in the Pathway from 5′-Hydroxyaverantin to Averufin in Aflatoxin Biosynthesis

2003 ◽  
Vol 69 (11) ◽  
pp. 6418-6426 ◽  
Author(s):  
Emi Sakuno ◽  
Kimiko Yabe ◽  
Hiromitsu Nakajima
Keyword(s):  
Aspergillus Parasiticus ◽  
Laser Desorption ◽  
Mass Spectrometry Analysis ◽  
Laser Desorption Ionization ◽  
Aflatoxin Biosynthesis ◽  
Cytosol Fraction ◽  
Ionization Time ◽  
Spectrometry Analysis ◽  
Flight Mass Spectrometry ◽  
Physicochemical Methods

ABSTRACT During aflatoxin biosynthesis, 5′-hydroxyaverantin (HAVN) is converted to averufin (AVR). Although we had previously suggested that this occurs in one enzymatic step, we demonstrate here that this conversion is composed of two enzymatic steps by showing that the two enzyme activities in the cytosol fraction of Aspergillus parasiticus were clearly separated by Mono Q column chromatography. An enzyme, HAVN dehydrogenase, catalyzes the first reaction from HAVN to a novel intermediate, another new enzyme catalyzes the next reaction from the intermediate to AVR, and the intermediate is a novel substance, 5′-oxoaverantin (OAVN), which was determined by physicochemical methods. We also purified both of the enzymes, HAVN dehydrogenase and OAVN cyclase, from the cytosol fraction of A. parasiticus by using ammonium sulfate fractionation and successive chromatographic steps. The HAVN dehydrogenase is a homodimer composed of 28-kDa subunits, and it requires NAD, but not NADP, as a cofactor for its activity. Matrix-assisted laser desorption ionization-time of flight mass spectrometry analysis of tryptic peptides of the purified HAVN dehydrogenase revealed that this enzyme coincides with a protein deduced from the adhA gene in the aflatoxin gene cluster of A. parasiticus. Also, the OAVN cyclase enzyme is a homodimer composed of 79-kDa subunits which does not require any cofactor for its activity. Further characterizations of both enzymes were performed.

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