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Measurement of nitric oxide levels in the red cell: validation of tri-iodide-based chemiluminescence with acid-sulfanilamide pretreatment

Measurement of nitric oxide levels in the red cell: validation of tri-iodide-based chemiluminescence with acid-sulfanilamide pretreatment
Measurement of nitric oxide levels in the red cell: validation of tri-iodide-based chemiluminescence with acid-sulfanilamide pretreatment
The tri-iodide-based chemiluminescence assay is the most widely used methodology for the detection of S-nitrosothiols (RSNOs) in biological samples. Because of the low RSNO levels detected in a number of biological compartments using this assay, criticism has been raised that this method underestimates the true values in biological samples. This claim is based on the beliefs that (i) acidified sulfanilamide pretreatment, required to remove nitrite, leads to RSNO degradation and (ii) that there is auto-capture of released NO by heme in the reaction vessel. Because our laboratories have used this assay extensively without ever encountering evidence that corroborated these claims, we sought to experimentally address these issues using several independent techniques. We find that RSNOs of glutathione, cysteine, albumin, and hemoglobin are stable in acidified sulfanilamide as determined by the tri-iodide method, copper/cysteine assay, Griess-Saville assay and spectrophotometric analysis. Quantitatively there was no difference in S-nitroso-hemoglobin (SNOHb) or S-nitroso-albumin (SNOAlb) using the tri-iodide method and a recently described modified assay using a ferricyanide-enhanced reaction mix at biologically relevant NO:heme ratios. Levels of SNOHb detected in human blood ranged from 20-100 nM with no arterial-venous gradient. We further find that 90% of the total NO-related signal in blood is caused by erythrocytic nitrite, which may partly be bound to hemoglobin. We conclude that all claims made thus far that the tri-iodide assay underestimates RSNO levels are unsubstantiated and that this assay remains the "gold standard" for sensitive and specific measurement of RSNOs in biological matrices.
0021-9258
26994-27002
Wang, Xunde
7ecc7619-20ee-4d23-8d48-b5b6af5f0853
Bryan, Nathan S.
709ff51c-c864-4862-9e3f-c5cfd3961025
MacArthur, Peter H.
465e8078-e5f7-463c-8248-b9b664e39e92
Rodriguez, Juan
055ad15f-3cf3-4366-a11c-9a313cf2fa60
Gladwin, Mark T.
7a8db6b5-2ee6-4e77-8915-0a2d33ef0d7f
Feelisch, Martin
8c1b9965-8614-4e85-b2c6-458a2e17eafd
Wang, Xunde
7ecc7619-20ee-4d23-8d48-b5b6af5f0853
Bryan, Nathan S.
709ff51c-c864-4862-9e3f-c5cfd3961025
MacArthur, Peter H.
465e8078-e5f7-463c-8248-b9b664e39e92
Rodriguez, Juan
055ad15f-3cf3-4366-a11c-9a313cf2fa60
Gladwin, Mark T.
7a8db6b5-2ee6-4e77-8915-0a2d33ef0d7f
Feelisch, Martin
8c1b9965-8614-4e85-b2c6-458a2e17eafd

Wang, Xunde, Bryan, Nathan S., MacArthur, Peter H., Rodriguez, Juan, Gladwin, Mark T. and Feelisch, Martin (2006) Measurement of nitric oxide levels in the red cell: validation of tri-iodide-based chemiluminescence with acid-sulfanilamide pretreatment. The Journal of Biological Chemistry, 281 (37), 26994-27002. (doi:10.1074/jbc.M603953200). (PMID:16845122)

Record type: Article

Abstract

The tri-iodide-based chemiluminescence assay is the most widely used methodology for the detection of S-nitrosothiols (RSNOs) in biological samples. Because of the low RSNO levels detected in a number of biological compartments using this assay, criticism has been raised that this method underestimates the true values in biological samples. This claim is based on the beliefs that (i) acidified sulfanilamide pretreatment, required to remove nitrite, leads to RSNO degradation and (ii) that there is auto-capture of released NO by heme in the reaction vessel. Because our laboratories have used this assay extensively without ever encountering evidence that corroborated these claims, we sought to experimentally address these issues using several independent techniques. We find that RSNOs of glutathione, cysteine, albumin, and hemoglobin are stable in acidified sulfanilamide as determined by the tri-iodide method, copper/cysteine assay, Griess-Saville assay and spectrophotometric analysis. Quantitatively there was no difference in S-nitroso-hemoglobin (SNOHb) or S-nitroso-albumin (SNOAlb) using the tri-iodide method and a recently described modified assay using a ferricyanide-enhanced reaction mix at biologically relevant NO:heme ratios. Levels of SNOHb detected in human blood ranged from 20-100 nM with no arterial-venous gradient. We further find that 90% of the total NO-related signal in blood is caused by erythrocytic nitrite, which may partly be bound to hemoglobin. We conclude that all claims made thus far that the tri-iodide assay underestimates RSNO levels are unsubstantiated and that this assay remains the "gold standard" for sensitive and specific measurement of RSNOs in biological matrices.

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Published date: 15 September 2006
Organisations: Clinical & Experimental Sciences

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Local EPrints ID: 337831
URI: http://eprints.soton.ac.uk/id/eprint/337831
ISSN: 0021-9258
PURE UUID: c124b455-bcab-44b4-86e6-78316a0af04b
ORCID for Martin Feelisch: ORCID iD orcid.org/0000-0003-2320-1158

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Date deposited: 04 May 2012 13:18
Last modified: 15 Mar 2024 03:41

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Contributors

Author: Xunde Wang
Author: Nathan S. Bryan
Author: Peter H. MacArthur
Author: Juan Rodriguez
Author: Mark T. Gladwin
Author: Martin Feelisch ORCID iD

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