PMID- 17421079
OWN - NLM
STAT- MEDLINE
DCOM- 20070531
LR  - 20190818
IS  - 0031-8655 (Print)
IS  - 0031-8655 (Linking)
VI  - 82
IP  - 5
DP  - 2006 Sep-Oct
TI  - A new approach for studying fast biological reactions involving nitric oxide: 
      generation of NO using photolabile ruthenium and manganese NO donors.
PG  - 1377-84
AB  - Nitric oxide (NO) is recognized as one of the major players in various 
      biochemical processes, including blood pressure, neurotransmission and immune 
      responses. However, experimental studies involving NO are often limited by 
      difficulties associated with the use of NO gas, including its toxicity and 
      precise control over NO concentration. Moreover, the reactions of NO with 
      biological molecules, which frequently occur on time scales of microseconds or 
      faster, are limited by the millisecond time scale of conventional stopped-flow 
      techniques. Here we present a new approach for studying rapid biological 
      reactions involving NO. The method is based on designed ruthenium and manganese 
      nitrosyls, [Ru(PaPy3)(NO)](BF4)2 and [Mn(PaPy3)(NO)](ClO4) (PaPy3H = 
      N,N-bis(2-pyridylmethyl)amine-N-ethyl-2-pyridine-2-carboxamide), which upon 
      photolysis produce NO on a fast time scale. The kinetics of the binding of the 
      photogenerated NO to reduced cytochrome c oxidase (CcO) and myoglobin (Mb) was 
      investigated using time-resolved optical absorption spectroscopy. The NO was 
      found to bind to reduced CcO with an apparent lifetime of 77 micros using the 
      [Mn(PaPy3)(NO)]+ complex; the corresponding rate is 10-20 times faster than can 
      be detected by conventional stopped-flow methods. Second-order rate constants of 
      approximately 1 x 10(8) M(-1) s(-1) and approximately 3 x 10(7) M(-1) s(-1) were 
      determined for NO binding to reduced CcO and Mb, respectively. The generation of 
      NO by photolysis of these complexes circumvents the rate limitation of 
      stopped-flow techniques and offers a novel alternative to study other fast 
      biological reactions involving NO.
FAU - Szundi, Istvan
AU  - Szundi I
AD  - Department of Chemistry and Biochemistry, University of California, Santa Cruz, 
      CA, USA.
FAU - Rose, Michael J
AU  - Rose MJ
FAU - Sen, Indranil
AU  - Sen I
FAU - Eroy-Reveles, Aura A
AU  - Eroy-Reveles AA
FAU - Mascharak, Pradip K
AU  - Mascharak PK
FAU - Einarsdottir, Olof
AU  - Einarsdottir O
LA  - eng
GR  - GM 53788/GM/NIGMS NIH HHS/United States
GR  - GM 61636/GM/NIGMS NIH HHS/United States
PT  - Journal Article
PT  - Research Support, N.I.H., Extramural
PL  - United States
TA  - Photochem Photobiol
JT  - Photochemistry and photobiology
JID - 0376425
RN  - 0 (Nitric Oxide Donors)
RN  - 31C4KY9ESH (Nitric Oxide)
RN  - 42Z2K6ZL8P (Manganese)
RN  - 7UI0TKC3U5 (Ruthenium)
SB  - IM
MH  - *Manganese
MH  - Nitric Oxide/*chemical synthesis/*radiation effects
MH  - Nitric Oxide Donors/*radiation effects
MH  - Oxidation-Reduction
MH  - *Ruthenium
MH  - Spectrophotometry
EDAT- 2007/04/11 09:00
MHDA- 2007/06/01 09:00
CRDT- 2007/04/11 09:00
PHST- 2007/04/11 09:00 [pubmed]
PHST- 2007/06/01 09:00 [medline]
PHST- 2007/04/11 09:00 [entrez]
AID - 10.1562/2006-07-25-rc-984 [doi]
PST - ppublish
SO  - Photochem Photobiol. 2006 Sep-Oct;82(5):1377-84. doi: 10.1562/2006-07-25-rc-984.