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A simplified procedure is described for the determination of hydroxyproline in human or monkey urine. In this procedure 1 ml of urine is subjected in succession to hydrolysis, oxidation, extraction, and color development. During these steps impurities and interfering substances are eliminated, thus resulting in a chromophore due to hydroxyproline alone.
The synthetic production of carbohydrate on a large scale is discussed. Three possible nonagricultural methods of making starch are presented in detail and discussed. The simplest of these, the hydrolysis of cellulose wastes to glucose followed by polymerization to starch, appears a reasonable and economic supplement to agriculture at the present time. The conversion of fossil fuels to starch was found to be not competitive with agriculture at the present time, but tractable enough to allow a reasonable plant design to be made. A reconstruction of the photosynthetic process using isolated enzyme systems proved technically much more difficult than either of the other two processes. Particular difficulties relate to the replacement of expensive energy carrying compounds, separation of similar materials, and processing of large reactant volumes. Problem areas were pinpointed, and technological progress necessary to permit such a system to become practical is described.
Six amino acids (glycine, alanine, aspartic acid, glutamic acid, serine, and threonine) obtained by hydrolysis of extracts have been quantitatively determined in ten collections of fines from five Apollo missions. Although the amounts found, 7-45 ng/g, are small, the lunar amino acid/carbon ratios are comparable to those of the carbonaceous chondrites, Murchison and Murray, as analyzed by the same procedures. Since both the ratios of amino acid to carbon, and the four or five most common types of proteinous amino acid found, are comparable for the two extraterrestrial sources despite different cosmophysical histories of the moon and meteorites, common cosmochemical processes are suggested.
The feasibility of using immobilized urease for urea removal from waste water for space system applications is considered, specifically the elimination of the urea toxicity problem in a 30-day Orbiting Frog Otolith (OFO) flight experiment. Because urease catalyzes the hydrolysis of urea to ammonia and carbon dioxide, control of their concentrations within nontoxic limits was also determined. The results of this study led to the use of free urease in lieu of the immobilized urease for controlling urea concentrations. An ion exchange resin was used which reduced the NH3 level by 94% while reducing the sodium ion concentration only 10%.
A method of extraction for amino acids from soils and sediments involving superheated water has been investigated. About 75-97 per cent of the amino acids contained in four soils of a soil profile from Illinois were extracted by this method. Deep penetration of water into soil aggregates and partial hydrolysis of peptide bonds during this extraction by water at high temperature are likely mechanisms responsible for the release of amino acids from samples. This extraction method does not require subsequent desalting treatments when analyses are carried out with an ion-exchange amino acid analyzer.
The formation of HCN, ammonium cyanide, alkylnitriles, aminoacetonitrile and its C- and N-methyl homologs was demonstrated earlier in a simulated Jovian atmosphere. The polymeric material resulting in these experiments was shown to give glycine, alanine, sarcosine, aspartic acid and some imino dibasic acids on acid hydrolysis, suggesting thereby the participation of the monomeric nitriles in the formation of the polymeric product(s). Further examination of products resulting from semicorona and arc discharge through a mixture of methane and ammonia has provided evidence for the formation of alkylaminopropionitriles as a complex mixture and also some pyridyl and pyrimidyl type heterocyclic compounds. A gas chromatograph/mass spectrometer examination of the heterocyclics showed resemblance with those found in some carbonaceous chondrites. The significance of these findings in relation to chemical evolution is discussed.
Human urinary protein was found to contain enzymes that hydrolyze leucyl-, alanyl-, and glycyl-prolyl-beta-naphthylamides. The kinetic constants of these enzymes were determined and their chemical properties studied. The pH optima for the hydrolysis of the various naphthylamides were also determined. Glycyl-prolyl-arylaminade was inhibited by Co(2+) and Mn(2+), while two other arylamidases were slightly activated by Co(2+). p-Chloromercuriphenyl-sulfonate and puromycin significantly inhibited leucyl and alanyl arylamidases. The mean values for 24-hour urinary output for leucyl-, alanyl-, and glycyl-prolyl arylamidases in normal human male subjects were 4.32, 9.97, and 2.2 units, respectively.
Aminomalononitrile (HCN trimer) reacts with electrophiles such as aldehydes and acrylonitrile under very mild conditions of temperature and pH to produce intermediates which, after acid hydrolysis, yield amino acids. The following amino acids have been identified and quantitated: glycine, D,L-erythro- and D,L-threo-beta-hydroxyaspartic acids, D,L glutamic acid, and D,L-threonine and allo-threonine. The mechanism of their formation and the possible significance of these reactions in prebiotic syntheses are discussed.
Experiments were conducted to study the pathway for the prebiotic origin of amino acids from hydrogen cyanide (HCN) under the action of ionizing radiation considered as an effective source of energy on the primitive earth. The irradiations were performed in a cobalt-60 source with a dose rate of 200,000 rad/hr. Seven naturally occurring amino acids are identified among the products formed by the hydrolysis of gamma-irradiated solutions of HCN: glycine, alanine, valine, serine, threonine, aspartic acid, and glutamic acid. The identity of these amino acids is established by gas chromatography and mass spectrometry. Control experiments provided evidence that the amino acids are not the result of contamination.
The interaction of Na2SO4(l) with NaCl(g), HCl(g) and H2O(g) was studied in atmospheric pressure flowing air and oxygen at Na2SO4(l) temperatures of 900 and 1000 C. Thermomicrogravimetric and high pressure mass spectrometric sampling techniques were used. Experimental results establish that previously reported enhanced rates of weight loss of Na2SO4(l) in the presence of NaCl(g) are due to the reaction: Na2SO4(c) + 2HCl(g) = 2NaCl(g) + SO2(g) + H2O(g) + 1/2O2(g) being driven to the right in flowing gas systems. The HCl(g) is the product of hydrolysis of NaCl caused by small but significant amounts of H2O(g) present in the system. Thermochemical calculations are used to show that even with sub-ppm levels of H2O(g) present, significant quantities of HCl(g) are produced.
The free amino (0.3 equiv/residue) and carboxyl (0.5 equiv/residue) groups of thermal polylysine increased dramatically on treatment with distilled water. The total hydrolysis of such a polymer was abnormal in that only about 50% of the expected amino acids were recovered. Poly (lysine-co-alanine-co-glycine) under usual conditions hydrolyzed completely in 8 hours; whereas, when it was pretreated with diazomethane, a normal period of 24 hours was required to give (nearly) the same amounts of each free amino acid as compared with those obtained from the untreated polymer. The amino groups of the basic thermal poly(amino acids) were sterically hindered. The existence of nitrogen atoms linking two or three chains and reactive groups (anhydride, imine) were proposed.
Attempts have been made to determine the age of biological samples by measuring the racemization of amino acids in protein samples. The pitfalls and inherent complications in diagenetic racemization studies are reviewed, and recent advances in improving techniques are outlined. Methodological topics include isolation of amino acids from geological samples, resolution of amino acid enantiomers, and the effects of acid hydrolysis. The theory and kinetics of amino acid racemization are discussed with attention to the derivation of the rate expression for amino acid racemization, isoleucine and the equilibrium constant, the mechanism of amino acid racemization, the racemization of 'bound' versus 'free' amino acids, and factors affecting the racemization rates of free amino acids in aqueous solution. Applications of amino acid racemization kinetics to geochronology is considered with reference to shells, marine sediments, and bones. Potential complications include heating and diagenesis, diagenetic formation of amino acids, the effect of clays, species effect, and contamination.
Among the three principal methods for precombustion desulfurization of coal, which include physical depyriting, chemical desulfurization, and coal conversion to low-sulfur liquid and gaseous fuels, the potential of chemical methods looks promising in terms of both total sulfur removal and processing cost. The principal chemical methods for coal desulfurization involve treatment with either oxidizing agents or basic media at elevated temperature and pressure. A description is given of some recent experimental results which show the feasibility of removing sulfur, particularly organic sulfur, from high-sulfur coals by a simple method of low-temperature chlorinolysis followed by hydrolysis and dechlorination. The chemical feasibility of sulfur removal by chlorinolysis rather than the detailed engineering process is emphasized.
The nonenzymatic, nontemplate catalysis of nucleotide polymerization by Pb(2+) ions, a possible prebiotic catalyst, is reported. Adenosine and uridine phosphoimidazoles were reacted in buffered solutions of lead salts and products were analyzed by means of paper chromatography and electrophoresis. In the presence of Pb(2+) ion at pH 8.0 and 7.0 the reaction is found to progress rapidly with excellent yields of oligomers, with optimal yields observed at pH 8.0. Little temperature dependence in the range 0 to 30 C is observed, however hydrolysis of the reaction products is minimal when the reaction is carried out at 0 C. Results show that the yield of oligomers is insensitive to mixing or the source of lead ions, indicating that naturally occurring minerals or precipitates could be a source of Pb(2+) ions under prebiotic conditions.
Graphite fibers released from composites during burning or an explosion caused shorting of electrical and electronic equipment. Silicon carbide, silica, silicon nitride and boron nitride were coated on graphite fibers to increase their electrical resistances. Resistances as high as three orders of magnitude higher than uncoated fiber were attained without any significant degradation of the substrate fiber. An organo-silicone approach to produce coated fibers with high electrical resistance was also used. Celion 6000 graphite fibers were coated with an organo-silicone compound, followed by hydrolysis and pyrolysis of the coating to a silica-like material. The shear and flexural strengths of composites made from high electrically resistant fibers were considerably lower than the shear and flexural strengths of composites made from the lower electrically resistant fibers. The lower shear strengths of the composites indicated that the coatings on these fibers were weaker than the coating on the fibers which were pyrolyzed at higher temperature.
These 210 citations from the international literature describe the production and/or utilization of most forms of biomass as a source of energy, fuel, food, and chemical intermediates or feedstocks. Biomass conversion by incineration, gasification, pyrolysis, hydrolysis, anaerobic digestion, or fermentation, as well as by catalytic, photosynthetic, chemosynthetic, and bio-electrochemical means are among the conversion processes considered. Discussions include biomass plantation and material productivity, transportation and equipment requirements, effects, comparisons of means and efficiencies of utilization and conversion, assessments of limitations, and evaluations of economic potential.
The paper deals with a study investigating the nature and rates of the hydrolic aging of a wide-band instrumentation magnetic recording tape which employs oxide and backcoat binders made of a polyester urethane elastomer. It was found that the primary mechanism of tape aging and degradation resulted from hydrolysis of its polyester urethane binder.
Experiments concerning the physical mechanisms for the abiotic generation and chemical mechanisms for the amplification of optical activity in biological compounds are reviewed. Attention is given to experiments involving the determination of the differential adsorption of racemic amino acids on d- and l-quartz, the asymmetric photolysis of racemic amino acids by circularly polarized light, and the asymmetric radiolysis of solid amino acids by longitudinally polarized electrons, and the enantiomeric enrichments thus obtained are noted. Further experiments on the amplification of the chirality in the polymerization of D, L-amino acid mixtures and the hydrolysis of D-, L-, and D, L-polypeptides are discussed. It is suggested that a repetitive cycle of partial polymerization-hydrolyses may account for the abiotic genesis of optically enriched polypeptides on the primitive earth.