Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0016632 (Fox)
 1,461 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In the preceding paper the mechanism of catalysis of the manganese-containing superoxide dismutase from Bacillus stearothermophilus was shown to involve a 'fast cycle' and a 'slow cycle' [McAdam, Fox, Lavelle & Fielden, 1977 (Biochem. J. 165, 71-79)]. Further properties of the enzyme was considered in the present paper. Pulse-radiolysis studies, under conditions of low substrate concentration to (i.e. when the fast cycle predominates), showed that enzyme activity decreases as pH increases (6.5-10.2). Activity was unaffected by the addition of H2O2 or NaN3 but slightly decreased by KCN. Both H2O2 and the reducing radical anion CO2-- caused a decrease in A480 of the native enzyme. The rate of the fast catalytic cycle was independent of temperature (5-55 degrees C), and as temperature increases the slow cycle becomes relatively more important. Arrhenius parameters of the rate contants were estimated. The possible identity of the various forms of the enzyme is considered.
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PMID:A pulse-radiolysis study of the manganese-containing superoxide dismutase from Bacillus stearothermophilus. 1 13

The proteins of vesicular stomatitis virus (VSV) were analyzed on the basis of charge as well as size in polyacrylamide gels containing urea and acetic acid. The phosphorprotein NS was resolved into two major species. The less phosphorylated NS1 species contained about 10% fewer phosphate residues than the second species, NS2. These two phosphorylated forms were compartmentalized both in the virus and in the infected cell cytoplasm. Cores from virions and the core-containing fraction of the infected cell cytoplasm contained only the NS1 form. All of the more highly phosphorylated NS2 form and some of the NS1 form were found to be free of cores, whether they were derived from virions or from the infected cell. Therefore, the degree of phosphorylation appeared to determine whether or not the NS protein became bound to VSV cores. Moreover, the amount of bound NS1 protein relative to nucleocapsids increased as the pH of the culture medium was raised from 6.6 to 7.4. Because an increased in pH increases VSV replication (Fiszman et al., J. Virol. 13:801-808, 1974; Palma and Huang, in W.S. Robinson and C.F. Fox, ed., Mechanisms of Virus Disease, ICN-UCLA Symposia, p. 87-100, 1974), the NS1 protein may either regulate overall VSV RNA synthesis or regulate the switch between transcription and replication.
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PMID:Effects of phosphorylation and pH on the association of NS protein with vesicular stomatitis virus cores. 2 35

In spite of remarkable therapeutic results obtained by gestagens with antiandrogenic activity, usually combined with estrogen, in oily seborrhea, acne, Fox-Fordyce disease, androgenetic alopecia and hirsutism many dermatologist still hesitate to treat the named disorders by hormones. The reason for their hesitation appears to be the erroneous belief, that the named disturbances represent hormonal disorders the treatment of which does not belong to dermatology. After a survey on the mechanism of action of antiandrogens the basic difference between androgen dependent skin disorders and endocrinopathies with manifestation on the skin and its appendages is explained. Androgen dependent skin disorders, like oily seborrhea and most cases of acne are not the result of endocrine disturbances in the sense of an pathologically increased or decreased production of sexual hormons. Administering sexual hormons the physician takes advantage of the sebosuppressive effect of female sexual hormons as he does of the antiallergic activity of the hormon cortisol (and related compounds) in the treatment of eczemas. The antiandrogenic treatment of androgenetic alopecia, hirsutism and androgenetic acne--with their underlying hormonal disturbance, consisting in an increased production of androgens, represents an quasi etiological therapy. As in these cases the hormonal disturbances finds its expression mainly or exclusively in disorders of the skin or hair growth, the dermatologist, preferentially in cooperation with endocrinogists and/or gynacologists remains entitled to take over the treatment. The available drugs are discussed and suggestions are made for their appropriate use.
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PMID:[Dermatologic indications for anti-androgenic treatment]. 8 9

A precursor of 5S ribosomal RNA from Bacillus subtilis (p5A rRNA, 179 nucleotides in length) is cleaved by RNase M5, a specific maturation endonuclease which releases the mature 5S rRNA (m5, 116 nucleotides) and precursor fragments derived from the 5' (21 nucleotides) and 3' (42 nucleotides) termini of p5A rRNA. Previous results (Meyhack, B., et al. (1978) Proc. Natl. Acad. Sci. U.S.A. 75, 3045) led to the conclusion that recognition elements in potential RNase M5 substrates mainly reside in the mature moiety of the precursor. Limited digestion of p5A rRNA with RNase T1 permitted the isolation of a number of test substrates which contained both precursor-specific segments and were unaltered in the immediate vicinity of the cleavage sites, but which differed in that more or less extensive regions of the mature moiety of the p5A rRNA were deleted. Tests of the capacity of these partial molecules to serve as substrates for RNase M5 indicate clearly that the enzyme recognizes the overall conformation of potential substrates, neglecting only the double-helical "prokaryotic loop" (Fox, G.E., & Woese, C.R. (1975) Nature (London) 256, 505).
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PMID:Involvement of the mature domain in the in vitro maturation of Bacillus subtilis precursor 5S ribosomal RNA. 10 77

Exposure of 32P-labelled human platelets to ionophore A23187 results in an increased incorporation of 32P into polypeptides with apparent mol.wts. of 47 000 (P47) and 20 000 (P20), whereas exposure to prostaglandin E1 results in increased labelling of polypeptides with apparent mol.wts. of 24 000 (P24) and 22 000 (P22) [Haslam, Lynham & Fox (1979) Biochem. J. 178, 397-406]. Labelled platelets that had been incubated with ionophore A23187 or prostaglandin E1 were sonicated and rapidly separated into three fractions by differential centrifugation. Electron microscopy and measurement of marker enzymes indicated that the 1300-19 000 gav. particulate fraction was enriched in granules, mitochondria and plasma membranes, that the 19 000-90 000 gav. particulate fraction was enriched in both intracellular and plasma membranes and that the 90 000 gav. supernatant contained only soluble proteins. 32P-labelled phosphopolypeptide P47 was present almost exclusively in the 90 000 gav. supernatant, whereas phosphopolypeptide P20 was largely dephosphorylated under fractionation conditions that protected other phosphopolypeptides. 32P-labelled phosphopolypeptide P24 was enriched in both particulate fractions, but particularly in the 19 000-90 000 gav. fraction, and may therefore be present in both the intracellular and plasma membranes. Phosphopolypeptide P22 appeared to be similarly distributed. Both particulate fractions were capable of the ATP-dependent oxalate-stimulated uptake of Ca2+. When the 19 000-90 000 gav. membrane fraction was prepared from platelets that had been incubated with ionophore A23187, active uptake of Ca2+ did not occur, but when this fraction was isolated from platelets that had been exposed to prostaglandin E1, uptake of Ca2+ was significantly greater than observed with the corresponding membranes from control platelets. It is suggested that phosphorylation of polypeptide P24 (or P22) by a cyclic AMP-dependent protein kinase may promote the active transport of Ca2+ out of the platelet cytosol.
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PMID:Subcellular distribution of the different platelet proteins phosphorylated on exposure of intact platelets to ionophore A23187 or to prostaglandin E1. Possible role of a membrane phosphopolypeptide in the regulation of calcium-ion transport. 12 Feb

The apparent affinity constants for the binding of Cs+, Rb+, K+, Li+, Tl+ and NH4+ to (Na+ + K+)-dependent adenosine triphosphatase from teleost gills were measured and the values discussed in terms of the ion-selectivity isotherm described by Eisenman & Krasne (1975) [in MTP International Review of Science: Biochemistry Series One (Fox, C.F., ed.), vol. 2, pp. 27--59, Butterworths University Park Press, Baltimore]. The ion selectivity of the present enzyme is remarkably similar to that from nerve and brain.
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PMID:The activation of sodium-plus-potassium ion-dependent adenosine triphosphatase from marine teleost gills by univalent cations. 14 Dec 77

In spite of considerable reasearch over many years in the field of automatic speech recognition (Underwood, 1977), practical devices capable of recognising unrestricted speech remain as science fiction rather than fact. Simultaneous display of speech as an aid for the deaf has however, been accomplished using manual data input devices (Newell and King, 1977; Newell, 1978; Downton and Newell; Fox et al, 1975; Hayward, 1978). In this application shorthand typing machines have been used, because only they can keep pace with speech (Seibel, 1964). Two possible machines are currently available for English Transcriptions; the Palantype (a British device) and the Stenograph (an American device). They are both based on the same fundamental principles, but differ mechanically and in the typing conventions they use. These differences suggest that one machine may be superior to the other as an input device for an aid for the deaf. This paper compares the two shorthand systems with a view to their potential use in a system providing a simultaneous transcript of speech for the deaf.
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PMID:A comparison of palantype and stenograph for use in a speech transcription aid for the deaf. 16 92

A discussion of the expected mechanism of radical reduction of carbonyl compounds by dihydroflavin as it relates to the structure of the carbonyl compound is provided. Factors which must be taken into account are the free energies of formation of the radical anions (CR2O), THE ACIDITY OF THE CONJUGATE ACID OF THE CARBONYL FUNCTION (R2C negative charge OH), and the stability of the carbanion species of the product [(-)CR2(OH)]. It is proposed that in those instances where the product alcohol can flavin radical to CR2O or CR2OH occurs, otherwise H transfer is the terminal step for dihydroflavin reductions. The free energy of formation of the radical species CH2OH obtained by acid-catalyzed electron transfer from dihydroflavin (Fred) to formaldehyde is shown to be less than the experimentally determined free energy of activation (increment F is not equal to exp) for the reduction of formaldehyde by dihydroflavin (i.e., Fred plus CH2O leads to Fox plus CH2OH). Therefore, the radical pair composed of dihydroflavin radical species serve as an intermediate in the reduction. Our proposed mechanism is: Fred plus CH2O ka[H3O] forms k-a[H2O] Frad CH2OH leads to kc Fox plus CH3OH. The value of kaah/k-a has been obtained from the calculated standard potential Eo' for Fred plus CH2O plus H forms Frad plus CH2OH. Assuming ka to represent a two-step process (i.e., Fred plus CH2O plus H k'a forms k'-a Fred plus CH2OH kb forms k-b Frad CH2OH, where ka equals (k'akb)/(k'-ak-b), the value of k'-a will equal 10-10 M-minus 1 sec-minus 1 and kb 10-9 M-minus 1 sec-minus 1. From k'a/k'-a and kb there can be computed the expected value of increment F is not equal to calc as a function of pH. Comparison of increment F is not equal to calc to increment F is not equal to exp reveals that increment F is not equal to calc varies from increment F is not equal to exp by only about 2kcal mol-minus 1 (8.4 kJ mol-minus 1) between pH 5 and 9. Similar considerations establish that radical intermediates should serve eminently well in dihydroflavin reduction of ethyl pyruvate, pyruvic acid, etc. In these cases, 1 e transfer should compete with H transfer to yield the carbanions as the immediate products. Similar comparisons suggest that dihydronicotinamide reduction proceeds via RPyH plus C negative charge O forms RPyH plus C-0minus +H forms -H RPyH plus C-OH forms RPy plus HC-OH.
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PMID:Radical mechanisms for 1,5-dihydroflavin reduction of carbonyl compounds. 24 Jan 60

The oxidation-reduction reactions of tetraacetylriboflavine in the presence of various metal ions in dimethylformamide have been investigated using the stopped-flow technique under anaerobic conditions. Dismutation kinetics in the presence of redox-inactive dissociated divalent metal ions such as Cd2+, Zn2+, and Fe2+ are typically triphasic. Metal ions act primarily upon an intermediate flavine dimer formed by fast association of flavoquinone and flavohydroquinone, resulting in a parallel formation and neutral and chelated radicals. A competition between metal ions and proton donors, e.g. the neutral flavohydroquinone (FredH3), is observed at the level of this intermediate complex. Small spectral changes occur secondarily as an ill-defined intermediate phase which could correspond to the reorganization of the solvation of radical chelate. The neutral radical is finally chelated at a much slower rate, the yield of total radical formation remaining almost unchanged during this kinetic phase. The oxidation of flavohydroquinone by ferric ions, either dissociated or strongly coordinated within a porphyrin, is complete and proceeds through biphasic kinetics. The first phase (Fred leads to F) is much faster than the second one (F leads to Fox). Dismutation resulting from the transient accumulation of neutral flavosemiquinone competes with the direct oxidation with ferric ions for the completion of the second oxidation step. The relative rate of dismutation is essentially limited by acidic-basic reactions in the absence of an excess of ferrous ion. The kinetic analysis of the direct oxidation reactions favors an outer-sphere mechanism for the electron transfer to the ferric ion, either free or strongly coordinated. The formation of a ferrous radical chelate can result from the dismutation reactions only when the amount of ferric ion initially present is not sufficient for complete oxidation.
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PMID:The kinetics of flavine oxidation-reduction. II. Metal ion interactions. 24 88

N-Ethylmaleimide (MalNEt) binds covalently and without specificity to accessible sulfhydryl residues in proteins. In some cases specificity has been imposed on this reaction by manipulating reaction conditions, yielding information concerning both enzyme mechanism and the identity of specific proteins (for example C.F. Fox and E.P. Kennedy (1965) Proc. Natl. Acad. Sci. u.s. 54, 891-899) and R.E. McCarty and J. Fagan (1973) Biochemistry 12, 1503-1507). We have examined the effects of MalNEt on the active accumulation of nine amino acids by Escherichia coli strains ML 308-225 and DL 54. Whole cells have been used in order that transport systems both dependent on and independent of periplasmic binding proteins could be studied under various conditions of energy supply for transport. Our results suggest that the systems transporting ornithine, phenylalanine and proline are those most likely to undergo inactivation by direct reaction of MalNEt with the transport apparatus, rather than merely via side effects such as interruption of their energy supply. The inhibition of proline transport is specifically enhanced by the presence of proline, competitive inhibitors of proline transport, or carbonylcyanide p-trifluoromethyoxyphenylhydrazone during MalNEt treatment. The other eight systems tested showed no analogous effects.
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PMID:The effects of N-ethylmaleimide on active amino acid transport in Escherichia coli. 31 57


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