Cyanamide: a new substrate for nitrogenase.

R W Miller; R R Eady

doi:10.1016/0167-4838(88)90129-x

Home/Archive/PubMed

PubMed · 3422164

Cyanamide: a new substrate for nitrogenase.

R W Miller·R R Eady

View original source ↗Export metadata ↓

Abstract

(1) Cyanamide (N identical to C-NH2) has been shown to be a substrate for purified Mo-nitrogenases of Klebsiella pneumoniae and Azotobacter chroococcum, with apparent Km values near 0.8 mM. (2) Reduction products were CH4, CH3NH2 and NH3 formed by pathways requiring 6 or 8 electrons: N identical to CNH2 + 6e + 6H+----CH3NH2 + NH3; N identical to CNH2 + 8e + 8H+----CH4 + 2NH3 (3) Acetylene reduction and hydrogen evolution were inhibited more than 75% by cyanamide (10 mM). Cyanamide also inhibited total electron flux at nitrogenase protein component ratios (Fe/MoFe) near 10. (4) Cyanamide was also a substrate for the recently isolated Va-nitrogenase of A. chroococcum, but with an apparent Km of 2.6 mM showed weaker binding and an 8-fold lower Vmax than did either Mo-nitrogenase. (5) The component ratios of nitrogenase proteins favouring CH4 formation was 3.5 Fe/MoFe protein and 1 Fe/VaFe protein.

Explore related subjects

Acetylene Ammonia Cyanamide Cyanides Hydrogen Kinetics Methane Methylamines Molybdenum Nitrogenase Oxidation-Reduction Substrate Specificity Vanadium Journal Article

Keep this discovery

Explore connections, maps & timelines

BibTeX RIS

R W Miller, R R Eady. 1988-02-10. Cyanamide: a new substrate for nitrogenase.. https://doi.org/10.1016/0167-4838(88)90129-x

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

PubMed2007

Highly selective Diels-Alder reactions of directly connected enyne dienophiles.

The paper describes the course of cycloadditions of Diels-Alder dienophiles containing linked enyne sites, each substituted with activating groups. Consistently, it was found that in the enyne cases the Diels-Alder reaction occurred specifically at the acetylenic center. Furthermore, it was found that the regiochemical sense of the cycloaddition was apparently determined by the remote activating group bound to the olefinic site. This remote acrylyl group totally dominated the course of the cycloaddition, relative to the activating group bound directly on the acetylene site. Explanations for these findings at the computational level are provided. The computations also rationalize the strong preference for cycloaddition to occur at the acetylene linkage and encompass the otherwise surprising regiochemical dominance by the remote ester on the olefinic site. The high selectivities available through such reactions provide important new opportunities in the synthesis of orsenillate type substructures that are found in a variety of natural products of contemporary interest.

Acetylene↗

PubMed2007

Enantioselective phenylacetylene addition to aldehydes and ketones catalyzed by recyclable polymeric Zn(salen) complex.

New polymeric Zn(salen) complex was employed in the enantioselective phenylacetylene addition to aldehydes and ketones to produce corresponding chiral secondary propargylic alcohols with yields (up to 96%) and enantioselectivity (up to 72%) and tertiary propargylic alcohols with yields (up to 79%) and enantioselectivity (up to 68%) at room temperature, with added advantage of four times reuse with retention of enantioselectivity.

Acetylene↗

PubMed2006

Using triethynylphosphine ligands bearing bulky end caps to create a holey catalytic environment: application to gold(I)-catalyzed alkyne cyclizations.

The synthesis, properties and catalytic uses of phosphinoalkynes bearing bulky end caps at the alkyne termini, that is, tris[(triarylsilyl)ethynyl]phosphines are reported. The most salient feature of the new phosphines is the holey molecular shape possessing a deep and large-scale metal-binding cavity. The holey phosphines displayed remarkable rate enhancement in the gold(I)-catalyzed six- and seven-membered ring forming cyclizations of acetylenic keto esters and 1,7-enynes. It is proposed that the cavity in the ligand forces a nucleophilic center (enol or alkene) of the acetylenic compounds close to the gold-bound alkyne, making ring-closing anti attack feasible.

Acetylene↗