Redox Pathways in DNA Oxidation:  Kinetic Studies of Guanine and Sugar Oxidation by Para-Substituted Derivatives of Oxoruthenium(IV)

2000 ◽  
Vol 39 (1) ◽  
pp. 44-49 ◽  
Author(s):  
Brian T. Farrer ◽  
H. Holden Thorp
Keyword(s):  
Oxidation Kinetic ◽  
Kinetic Studies ◽  
Dna Oxidation ◽  
Derivatives Of

scholarly journals The Structure and Function of Paraoxonase-1 and Its Comparison to Paraoxonase-2 and -3

Molecules ◽  
2020 ◽  
Vol 25 (24) ◽  
pp. 5980
Author(s):  
Ajda Taler-Verčič ◽  
Marko Goličnik ◽  
Aljoša Bavec
Keyword(s):  
Catalytic Mechanism ◽  
Kinetic Studies ◽  
Amino Acid Sequences ◽  
Site Directed Mutagenesis ◽  
Paraoxonase 1 ◽  
Homocysteine Thiolactone ◽  
Substrate Promiscuity ◽  
Serum Paraoxonase ◽  
And Function ◽  
Derivatives Of

Serum paraoxonase-1 (PON1) is the most studied member of the group of paraoxonases (PONs). This enzyme possesses three enzymatic activities: lactonase, arylesterase, and paraoxonase activity. PON1 and its isoforms play an important role in drug metabolism as well as in the prevention of cardiovascular and neurodegenerative diseases. Although all three members of the PON family have the same origin and very similar amino acid sequences, they have different functions and are found in different locations. PONs exhibit substrate promiscuity, and their true physiological substrates are still not known. However, possible substrates include homocysteine thiolactone, an analogue of natural quorum-sensing molecules, and the recently discovered derivatives of arachidonic acid—bioactive δ-lactones. Directed evolution, site-directed mutagenesis, and kinetic studies provide comprehensive insights into the active site and catalytic mechanism of PON1. However, there is still a whole world of mystery waiting to be discovered, which would elucidate the substrate promiscuity of a group of enzymes that are so similar in their evolution and sequence yet so distinct in their function.

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