What's the difference between hydrocarbon and methenyl?
Hydrocarbon
Definition:
(n.) A compound containing only hydrogen and carbon, as methane, benzene, etc.; also, by extension, any of their derivatives.
Example Sentences:
(1) The high transition enthalpy for kerasin is ascribed to a lesser accommodation of gauche conformers in the hydrocarbon chains just below the transition temperature.
(2) Aryl hydrocarbon hydroxylase (AHH) inducibility, carbon monoxide in expired air (CO), serum gammaglutamyl-transferase (GGT), and total cholesterol were compared in equal-sized, age-matched samples of healthy middle-aged males born in 1921, 1934-1936, and 1946 attending the ongoing preventive medical population program in Malmö.
(3) The length of the hydrocarbon chains of the surface-modified silica supports had no significant influence on the selectivity.
(4) The specificity of binding to microsomal proteins of metabolically activated hydrocarbons has been studied.
(5) Aryl hydrocarbon (benzo(a)pyrene) hydroxylase is present and inducible in Buffalo rat liver cells in culture.
(6) The possible occupational cause of the disease, as more solvents in the mud have the structure of aromatic hydrocarbons is discussed.
(7) Experiments with a series of adsorbents homologous with CPAD-Sepharose, in which the length of the hydrocarbon chain was varied, provided strong evidence of hydrophobic interactions, in addition to ionic interactions, in the binding of these proteins to CPAD-Sepharose.
(8) In the hydrocarbon promotion study, dose related increases were observed in the incidence of ACF in male rats promoted with UG or 50 ppm TMP for 24 or 60 weeks.
(9) The results also demonstrated that there was not any apparent correlation between the receptor-binding avidities and in vitro monooxygenase enzyme-induction potencies for the most active polynuclear aromatic hydrocarbons.
(10) Both main-stream and side-stream cigarette smoke condensates and some fractions, containing water-soluble bases, water-insoluble bases, and polycyclic aromatic hydrocarbons, were found to induce AHH activity in lung and liver, the lung being induced to the greatest extent.
(11) Pancreas transplantation offers the possibility of preventing the development and progression of diabetic lesions by adequate control of hydrocarbon metabolism.
(12) A comparison of the relative cytosolic Ah (9S) receptor binding affinities and aryl hydrocarbon hydroxylase (AHH) induction potencies of these hydrocarbons with their 4S protein binding affinities demonstrated the following: five compounds, namely 1,2,5,6-dibenz[a]-anthracene, 1,2,3,4-dibenz[a]anthracene, picene, benzo[a]pyrene and 3-methylcholanthrene exhibited high to moderate binding affinities for the 4S and 9S cytosolic proteins (EC50 values less than 10(-6) M) and induced AHH in rat hepatoma cells; three compounds, namely perylene, benzo[e]pyrene and benzo[g,h,i]perylene exhibited high affinities for the 4S binding protein (1.25 X 10(-7), 4.4 X 10(-8) and 2.9 X 10(-8) M, respectively) and low affinities (EC50 values greater than 10(-5) M) for the Ah receptor protein; moreover these three compounds did not induce AHH in rat hepatoma H-4-II E cells in culture.
(13) It was found that HBSAg was strongly bound to straight hydrocarbon chains with more than seven carbon atoms.
(14) The parent hydrocarbons and the related K-region dihydrodiols induced some sister-chromatid exchanges but they were considerably less active than these two non-K-region diols.
(15) The effect of various fuel additives on the ability of platinum-palladium catalytic converters to remove the carbon monoxide and hydrocarbon components of automotive exhaust has been examined.
(16) Other chlorinated hydrocarbons as decachlorobiphenyl, pentachloronaphthalene, hexachloronaphthalene and hexachlorostyrene were identified, but not quantified.
(17) It has been estimated that natural oil seeps may also contribute as much as 10% of the hydrocarbons in the global marine environment.
(18) The metabolic fate of the carcinogenic aza-aromatic hydrocarbon 7-methyl[7-(14)C]benz[c]acridine (14C-7MBAC) was studied in hepatocytes freshly isolated from untreated, phenobarbital-pretreated and 3-methylcholanthrene-pretreated rats.
(19) Renal cytochrome P450, aryl hydrocarbon hydroxylase, 7-ethoxycoumarin-O-deethylase, and benzphetamine N-demethylase were increased after partial hepatectomy by 84%, 360%, 165% and 406%, respectively.
(20) Antioxidants devoid of hydrocarbon tails, are 10-20 fold more potent LPO inhibitors than the corresponding AOs with hydrocarbon tails.
Methenyl
Definition:
(n.) The hypothetical hydrocarbon radical CH, regarded as an essential residue of certain organic compounds.
Example Sentences:
(1) The enzyme catalyzes the hydrolysis of methenyl-H4MPT to formyltetrahydromethanopterin (formyl-H4MPT).
(2) A DNA clone complementary to the messenger RNA encoding the human trifunctional enzyme 5,10-methylenetetrahydrofolate dehydrogenase-5,10-methenyl-tetrahydrofolate cyclohydrolase-10-formyltetrahydrofolate synthetase has been isolated from a lambda gt10 library.
(3) The relative configuration of the pterin moiety of 5,6,7,8-tetrahydromethanopterin 1, a coenzyme isolated from methanogenic archaea, has been determined by two-dimensional NMR spectroscopy of N5,N10-methenyl-5,6,7,8-tetrahydromethanopterin 2 to be rel-(6R; 7S; 11R).
(4) We also measured the activities of another three enzymes of the folic acid cycle, viz., 5,10-methylene-H4folate dehydrogenase, 10-formyl-H4folate synthetase, and 5,10-methenyl-H4folate cyclohydrolase, as well as the enzyme cystathionine beta-synthase.
(5) Evaluation of the reaction equilibrium indicated that the methenyl derivative was favored over 5-formyltetrahydromethanopterin, with a much higher equilibrium constant than for the analogous reaction of tetrahydrofolate derivatives.
(6) Escherichia coli DNA photolyase contains 1,5-dihydro-FAD (FADH2) plus 5,10-methenyl-tetrahydrofolate (5,10-CH+-H4folate).
(7) IR spectrophotometry of the crystals embedded in potassium bromide disc showed specific spectra in the 1400-800 cm-1 wave number range and typical peaks on wave number assigned for hydroxy or amine (3420 cm-1), aromatic hydrogen (3060 cm-1), methyl, methylenic, or methenyl (2960-2860 cm-1), and carbonyl (1715 cm-1) groups can be demonstrated.
(8) The three activities are thus shown to reside in a protein composed of two apparently identical subunits, and the trivial name formyl-methenyl-methylenetetrahydrofolate synthetase(combined) is proposed for this enzyme to suggest the multiple catalytic activities associated with the single protein species.
(9) A method has been devised for the cytochemical demonstration of 5-formyl tetrahydrofolate cyclodehydrase and 5,10-methenyl tetrahydrofolate cyclohydrolase activity which uses 5-formyl tetrahydrofolate or 5,10-methenyl tetrahydrofolate as substrate respectively, blocking possible interferences by other enzymes, and allows the nonenzymatic reduction of nitro-blue tetrazolium by 5,10-methenyl tetrahydrofolate formed by the action of the cyclodehydrase on the substrate 5-formyl tetrahydrofolate, and by 10-formyl tetrahydrofolate formed by the action of cyclohydrolase on the substrate 5,10-methenyl tetrahydrofolate, thus revealing intracellular sites of enzyme activity.
(10) In eucaryotes, 10-formyltetrahydrofolate (formyl-THF) synthetase, 5,10-methenyl-THF cyclohydrolase, and NADP(+)-dependent 5,10-methylene-THF dehydrogenase activities are present on a single polypeptide termed C1-THF synthase.
(11) A second enzyme, cyclohydrolase, converts 5,10-methenyl tetrahydrofolate to 10-formyl tetrahydrofolate.
(12) 5,10[14C]methylene H4folate and 5,10[14C]methenyl H4folate also serve as precursors of formic acid in the poison gland, suggesting that they are intermediates in the pathway.
(13) C1-tetrahydrofolate (THF) synthase is a trifunctional protein possessing the activities 10-formyl-THF synthetase, 5,10-methenyl-THF cyclohydrolase, and 5,10-methylene-THF dehydrogenase.
(14) The product of formyl transfer by the purified enzyme was shown by a number of criteria to be 5-formyl-H4MPT, as opposed to 10-formyl-H4MPT or 5,10-methenyl-H4MPT.
(15) When methanogenesis from the non-physiological donors was followed under a nitrogen atmosphere, the C1 moiety from each compound underwent a disproportionation, forming methenyl-H4MPT+ and methane.
(16) The enzyme 5-formyl tetrahydrofolate cyclodehydrase plays an important role in the conversion of 5-formyl tetrahydrofolate to 5,10-methenyl tetrahydrofolate.
(17) Similarly, the nonenzymatic hydrolysis of methenyl-H4MPT is highly dependent on pH and buffer.
(18) Cell extracts of Methanobacterium thermoautotrophicum possess a methenyl-tetrahydromethanopterin (methenyl-H4MPT) cyclohydrolase.
(19) In eukaryotes, this enzyme is trifunctional and contains the activities of 10-formyl-H4folate synthetase, 5,10-methenyl-H4folate cyclohydrolase, and 5,10-methylene-H4folate dehydrogenase.
(20) The compounds tested served as substrates for the enzymatic synthesis of methenyl-H4MPT+.