TITLE:
Biological implications of 2-chlorocyclohexa-2,5-diene-1,4-dione toward ribonuclease A
AUTHORS:
Albert R. Vaughn, Caitlin B. Redman, Sophia M. Kang, Jisook Kim
KEYWORDS:
Chlorobenzoquinone; PAH; Protein Modification; Ribonuclease A
JOURNAL NAME:
Advances in Bioscience and Biotechnology,
Vol.4 No.1,
January
21,
2013
ABSTRACT: 2-Chlorocyclohexa-2,5-diene-1,4-dione
(CBQ) or 2-chloro1,4-benzquinone is one of the common metabolites of polycyclic
aromatic hydrocarbons generated through industrial processes. This report describes
the biological effects of CBQ toward ribonuclease A (RNase). We also investigated
the inhibition of RNase modifications and the reactivity of CBQ toward selected
amino acids. The study was carried out by incubating RNase or amino acids with
CBQ in a concentration- and a time-dependent manner at 37°C and pH 7.0. SDS-PAGE
results showed oligomerization as well as polymeric aggregation of RNase when
incubated with CBQ as early as in 10 min. CBQ-induced RNase modifications were
inhibited in the presence of NADH or ascorbic acid. CBQ reactivity toward selected
amino acids was also evaluated by determining the second-order rate constants for
the reactions of CBQ with selected amino acids. It was found that the reactivity
toward CBQ decreased in the order of lysine > threonine
> serine >> aspartate > cysteine.