Linked Life Data

6592986

Source:http://linkedlifedata.com/resource/pubmed/id/6592986

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1984-11-14
pubmed:abstractText
Micromethods of direct chemical coupling have been developed for several different enzyme reactions, using the principles of flow injection analysis. Samples of 1-25 microliters are injected into a flowing stream of color-forming reagents and the peak of color change is measured after about 1 min. Alternatively, continuous slow infusion of a reacting system (5-100 microliters/min) gives a continuous change of color which can be monitored to derive enzyme reaction rates. These techniques are highly sensitive, requiring a few nanomoles of the substance being detected. Phosphate, ammonia, dithionite, creatine, and hydrazine have been measured. Consumption of reagents is less than 75 ml per hour; typical sample throughout is 30-40 samples per hour by the injection method, and 5 samples per hour by continuous infusion. The procedure has been applied to nitrogenase, continuously monitoring creatine produced from creatine phosphate by creatine kinase which is used to supply a constant level of ATP for nitrogenase. In this way nitrogenase activity can be determined over a wide range of enzyme concentrations. Production of inorganic phosphate directly from ATP, by injection of formaldehyde-quenched samples, was used when coupling to creatine kinase was not possible. Both injection of aliquots and continuous infusion were used for detection of hydrazine during nitrogenase reduction of azide, and the injection method has been used for ammonia assay during dinitrogen reduction. Dithionite oxidation was measured directly from decolorization of iodine, after trapping both dithionite and bisulfite with formaldehyde.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
0003-2697
pubmed:author
pubmed:issnType
Print
pubmed:day
1
pubmed:volume
140
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
434-42
pubmed:dateRevised
2008-11-21
pubmed:meshHeading
pubmed:year
1984
pubmed:articleTitle
Chemically coupled spectrophotometric assays based on flow injection analysis: determination of nitrogenase by assays for creatine, ammonia, hydrazine, phosphate, and dithionite.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't