Premium
Effect of salts on the activity of nitrate reductase from the photosynthetic bacterium Rhodobacter sphaeroides SW
Author(s) -
Paggi Roberto A.,
De Castro Rosana E.,
Kerber Norma L.,
Garcia Augusto F.
Publication year - 1995
Publication title -
journal of basic microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.58
H-Index - 54
eISSN - 1521-4028
pISSN - 0233-111X
DOI - 10.1002/jobm.3620350113
Subject(s) - rhodobacter sphaeroides , chemistry , divalent , nitrate reductase , rhodospirillaceae , rhodobacter , enzyme , rhodospirillales , nitrate , enzyme assay , photosynthesis , stereochemistry , inorganic chemistry , medicinal chemistry , biochemistry , organic chemistry , gene , mutant
The effect of different salts on the nitrate reductase (NR) activity of Rhodobacter sphaeroides SW was studied. An increase of the activity in the presence of monovalent cations was observed (90, 80 and 77% with Na + , K + and NH 4 + , respectively), whereas divalent cations inhibited the enzyme activity (30 and 85% with Ca 2+ and Mg 2+ ). Both activation or inhibition of the NR activity were reversible. These results could be explained by the interaction of cations with negatively charged amino acids. On the other hand, several anions were also effective in stimulating NR activity (Cl − > NO 3 −> Br − > I − > SCN − ), suggesting that the degree of hydration of the enzyme molecule might influence its activity. Finally, the effect of salts on the NR activity of R. sphaeroides SW can be atributed to both electrostatic and hydrophobic interactions.