Structure of Dihydrodiphosphopyridine Nucleotide

Shifrin, Sidney; Kaplan, Nathan O.

doi:10.1038/1831529a0

Cited by 41 publications

(14 citation statements)

References 6 publications

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“…Comparisons describing the viscosity of steam at atmospheric pressure in the range 100-800 °C are contained in figure 13. The 1964 ST preferred Shifrin's data [65] which were systematically higher than Bonilla's [661. The figure brings out the fact that this bias was subsequently justified by the newer measurements performed by Latto [67], Sato et a1.…”

Section: Selected Experimental Datomentioning

confidence: 91%

Section: Viscosity Of Steam At Atmospheric Pressurementioning

confidence: 99%

“…In 1964 there existed only two sets of measurements of the viscosity of steam at atmospheric pressure in a wide range of temperatures, namely those of Shifrin [65] and Bonilla, Wang, and Weiner [66]. The sets have a systematic, mutual deviation reaching 4% and the 1964 ST compromised with the linear equation of Shifrin [65]. The more recent measurements of Latto [67], Sato and coworkers (extrapolated) [68,69] and Timrot and co-workers [70] agreed with the 1964 ST within their quoted experimental error.…”

Section: Viscosity Of Steam At Atmospheric Pressurementioning

confidence: 99%

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Viscosity of water substance—new international formulation and its background

Nagashima

1977

Journal of Physical and Chemical Reference Data

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The paper traces the development of our knowledge of the viscosity of water and steam over the last decade, that is over the period of intense experimental and analytic activity which separates the promulgation of the 19M Supplementary Release on Transport Properties of the Sixth ICPS from the recently announced Release on Dynamic Viscosity of Water Substance. As a result of this work, which was largely stimulated by the activities of the International Association for the Properties of Steam, the new internationally recognized skeleton table and the international1y recommended equations cover the wide range 01 pressures and temperatures of 0-100

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Section: Selected Experimental Datomentioning

confidence: 91%

Section: Viscosity Of Steam At Atmospheric Pressurementioning

confidence: 99%

Section: Viscosity Of Steam At Atmospheric Pressurementioning

confidence: 99%

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Viscosity of water substance—new international formulation and its background

Nagashima

1977

Journal of Physical and Chemical Reference Data

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“…Weber suggested (355), on the basis of interference of this energy t,ransfer by pyrophosphorolysis of DPNH, that a complex is formed between the adenine and the dihydropyridine. This concept has been supported by studies with the alpha isomer of DPNH where it has been shown that there is little transfer between the purine and pyridine moieties (143,279). We have suggested (277) that transfer would occur most efficiently when the planes of the adenine and dihydronicotinamide rings are parallel to one another as shown in Figure 14.…”

Section: Beef Heart Lactic Dehydrogenase (Ldh)supporting

confidence: 54%

Coenzyme Binding

Shifrin¹,

Kaplan²

1960

Advances in Enzymology - And Related Areas of Molecular Biology

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“…The probable involvement of the catalytically important sulfhydryl groups in electron transfer or the binding of substrates [40,41] suggests that reaction substrates may be able to protect these groups from attack by p-hydroxymercuribenzoate. In attempts to assess the importance of sulfhydryl groups at the catalytic centres experiments were performed to evaluate the ability of reactants to prevent p-hydroxymercuribenzoate inhibition.…”

Section: Protection Of -Sh Residues By Substratesmentioning

confidence: 99%

The Purification and Properties of Cyclohexanone Oxygenase from Nocardia globerula CL1 and Acinetobacter NCIB 9871

Donoghue

Norris

Trudgill

1976

European Journal of Biochemistry

341

219

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Cyclohexanone oxygenases from Nocardia globerula CL1 and Acinetobacter NCIB 9571 have been purified 12‐fold and 35‐fold respectively and each gives a single symmetrical sedimentation peak in the ultracentrifuge and a single protein band on 2.25 nm average pore radius polyacrylamide gels. The enzyme from N. globerula has a molecular weight of 53000 while that from Acinetobacter has a molecular weight of about 59000. Each is a single polypeptide chain with one mole of bound FAD per mole of protein that does not dissociate during purification. Acidification of the Acinetobacter enzyme in the presence of (NH4)2SO4 releases the bound FAD and yields native apoenzyme from which the active holoenzyme can be reconstituted. The apparent dissociation constant for the FAD is 40 nM. The near unitary stoichiometry of cyclohexanone, NADPH and oxygen consumption is typical of mixed function oxygenases with external electron donors. The oxygenated product has been identified as 1‐oxa‐2‐oxocycloheptane thus placing these enzymes in the small group of lactone and ester‐forming oxygenases. Their correct systematic name is cyclohexanone. NADPH: oxygen oxidoreductase (1,2‐lactonizing) (EC 1.14.13.‐). A functionally essential sulfhydryl group is present at the catalytic centre of both enzymes but there is no reliable indication from inhibitor studies that they contain any functional metal ion. The three titratable sulfhydryl groups of the Acinetobacter enzyme are not equivalent since reaction with one of them selectively inhibits catalytic activity. Protection against sulfhydryl active agents is afforded by NADPH but not by cyclohexanone. The N. globerula enzyme has a pH optimum of 8.4, apparent Km values of 1.56 μM and 31.3 μM for cyclohexanone and NADPH respectively and a catalytic centre activity of 1018 ml substrate transformed × mol enzyme−1× min−1. The Acinetobacter enzyme has a pH optimum of 9.0, apparent Km values of 6.9 tM and 17.8 μM and a catalytic centre activity of 1390 mol × mol enzyme−1× min−1. Both enzymes display absolute specificity for electron donor which contrasts with the broad specificity for ketone substrate. An enzyme‐cyclohexanone complex has been detected by difference spectroscopy only in the case of the Nocardia enzyme. Rapid reduction of the enzyme‐bound FAD occurs upon addition of NADPH in the absence of cyclohexanone. Titration of enzyme with NADPH under anaerobic conditions and anaerobic photoreduction in the presence of EDTA have not revealed the formation of any stable flavin semiquinones. These enzymes bear a strong resemblance to several of the monooxygenases that hydroxylate aromatic compounds.

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Structure of Dihydrodiphosphopyridine Nucleotide

Cited by 41 publications

References 6 publications

Viscosity of water substance—new international formulation and its background

Viscosity of water substance—new international formulation and its background

Coenzyme Binding

The Purification and Properties of Cyclohexanone Oxygenase from Nocardia globerula CL1 and Acinetobacter NCIB 9871

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