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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
12
pubmed:dateCreated
1998-4-30
pubmed:abstractText
Inducible nitric oxide synthase (iNOS; EC 1.14.13.39) catalyzes the NADPH-dependent oxidation of one of the free guanidino nitrogens of L-Arg to form nitric oxide and L-citrulline. Analogues of L-Arg and the inhibitor, L-N6-(1-iminoethyl)lysine, were used to define structural elements required for the binding and catalysis of compounds. L-Arg analogues with sequentially shorter methylene spacing between the guanidino group and the amino acid portion of the molecule were not iNOS substrates but were reversible inhibitors. L-Arg analogues such as agmatine with a hydroxyl substitution at the 2-amino position were substrates. Desaminoarginine was not a substrate but a reversible inhibitor. Desaminoarginine, agmatine, and argininic acid bound to the enzyme to give type I difference spectra similar to that of L-Arg. The amidino compounds L-N6-(1-iminoethyl)lysine, L-N5-(1-iminoethyl)ornithine, and N5-(1-iminoethyl)cadaverdine, but not N6-(1-iminoethyl)-6-aminocaproic acid, were NADPH-dependent, irreversible inactivators of iNOS. For both the L-Arg and L-N6-(1-iminoethyl)lysine analogues, the 2-amino group appeared to play an important role in catalytic events leading to either substrate turnover or mechanism-based inactivation. Inactivation of iNOS by L-N6-(1-iminoethyl)lysine was NADPH- and dioxygen-dependent, but low incorporation of radiolabel with DL--4, 5-3H]-N6-(1-iminoethyl)lysine indicates that the mechanism of enzyme inactivation is not covalent modification of the protein.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
24
pubmed:volume
37
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
4174-80
pubmed:dateRevised
2011-10-27
pubmed:meshHeading
pubmed:year
1998
pubmed:articleTitle
Structural requirements for human inducible nitric oxide synthase substrates and substrate analogue inhibitors.
pubmed:affiliation
Department of Biochemistry, Merck Research Laboratories, Rahway, New Jersey 07065, USA. stephanvgrant@merck.com
pubmed:publicationType
Journal Article