Enzymatic transamination consists of the enzyme catalyzed reversible transfer of the alpha amino nitrogen of an amino acid to an alpha-keto acid with the synthesis of a second amino acid and a second alpha-keto acid. Enzymes catalyzing different transamination reactions are found widely distributed in animal tissues and have been shown to change in activity in some tissues during disease (1-3). These observations prompted the present study to determine if transaminase activity could be demonstrated in human serum and blood cellular elements and, if so, to study any variations in activity of this enzyme in the blood of normal and diseased man. METHODS AND MATERIALSThe two transaminases found most active in animal tissues are:1. "Glutamic-oxalacetic transaminase" Aspartate + alpha-keto glutarate = glutamate + oxalacetate 2. "Glutamic-pyruvic transaminase"Alanine + alpha-keto glutarate = glutamate + pyruvate When aspartate or alanine are incubated with alphaketo glutarate and a source of enzyme, the rate of production of glutamate may be taken as a measure of transaminase activity. The amount of glutamate produced after a given incubation period under standardized conditions was measured by quantitative paper chromatographic analysis (4).One-tenth molar solutions of I-aspartate, I-alanine, and alpha-keto glutarate were prepared in 0.06 M phosphate buffer and the pH of the solutions adjusted to pH 7.6. For serum transaminase determinations, 0.5 ml. of clear, non-hemolyzed serum, 1.5 ml. of 0.06 M phosphate buffer, pH 7.6, and 0.5 ml. of either the alanine or aspartate solutions were incubated for ten minutes at 37°C. At this time, 0.5 ml. of the alpha-keto glutarate solution was added and the incubation continued for 18 hours. For whole blood hemolysate transaminase determinations, equal volumes of blood and distilled water were shaken together for ten minutes, 1.0 ml. of the hemolysate was added to 1.0 ml. of the phosphate buffer, and the substrates added as above. The time of incubation of the hemolysate substrate mixture was three hours.At the end of the incubation period, proteins were separated by adding 7.0 ml. of absolute ethyl alcohol, centrifuging for ten minutes, and washing the precipitate with 5 ml. of 70 per cent ethanol. The supernatant was evaporated to dryness over a water bath and the residue dissolved in 1.0 ml. of 0.06 M phosphate buffer. Aliquots of 0.05 ml. were then applied to Whatman No. 1 filter paper and chromatographed by the descending method for 18 hours, using phenol saturated with water as solvent and water saturated with phenol to saturate the atmosphere of the tank. The papers were then removed and dried in air at room temperature (5). The position of the amino acids was located by spraying the paper with a 0.1 per cent solution of ninhydrin in butanol and heating gently with an infra-red lamp.The areas of paper corresponding to glutamate were cut out, rolled, and placed in test tubes. Elution of the amino acid from the paper and quantitative color development with ninhydrin were perf...

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Summary. When human erythrocytes were incubated in vitro with 14C-labeled free fatty acids bound to serum albumin, labeled fatty acids were incorporated into erythrocyte triglycerides and phospholipids. The first step in this reaction was the transfer of free fatty acids from the albumin to the cells. This transfer was rapid and reversible. The acids were distributed between albumin and cells according to the relative quantities of albumin and cells present. Each acid had a different distribution coefficient. At equilibrium, relatively larger fractions of the stearic and palmitic acids and smaller fractions of the oleic and linoleic were associated with the cells. All these fatty acids were then slowly incorporated into phospholipids and triglycerides. The rate of incorporation of each was a function of its concentration in the cells, but larger fractions of the oleic and linolei, were incorporated than of the stearic, palmitic, myristic, or lauric. The two processes of transfer and incorporation thus had almost opposite selectivities for the different fatty acids. As a result, the fatty acids incorporated into triglycerides and phospholipids resembled in composition the fatty acids on the albumin except for moderately less stearic acid.

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b A hydrogen flame ionization detector has been developed that is sensitive only to compounds containing chlorine, bromine, iodine, and phosphorus. A wire mesh that has been treated with sodium hydroxide, or one of several other hydroxides or salts, is heated in a hydrogen flame.The presence of a compound containing halogens or phosphorus in the flame gores increases the rate of volatilizotion of sodium or other metal vapor from the screen. This metal vapor is then detected by flame ionization in a second hydrogen flame. Nanogram quantities of hologen-contoining compounds in the presence of much larger quantities of compounds not containing these elements were specifically detected.HEN ORGANIC CuMPomns are w burned m a hydrogen flame, the electrical Conductivity of the flame is increased. This is the basis of operation of the hydrogen flame ionization detector (9). Recently it was noted that compounds containing halogens or phosphorus increased the electrical conductivity more when a wire probe containing a sodium compound was heated in the flame. The presence of the probe thus caused the responsiveness of the detector to these compounds to be enhanced (5). Further study revealed that adding a halogen-containing compound to the flame gases could increase the rate of volatilization of a number of different metals from a wire heated in a flame. The increased rate of volatilization of these metals was manifested both by an increase in the emission of the light characteristic of the metal, and, in the case of metals with sufficiently low ionization potentials, by an increase in the electrical conductivity of the flame. The mechanism of the enhanced sensitivity of the detector to compounds containing halogens and phosphorus thus appeared to he that the products of combustion of these compounds reacted with the probe to increase the rate of release of sodium from it and the sodium vapor was then excited and ionized in the flame.This effect has been utilized in the design of a hydrogen flame ionization detector that is sensitive only to com-1416 e ANALYTICAL CHEMISTRY pounds containing chlorine, bromine, iodine, or phosphorus. Hydrogen gas was added to the effluent of the column and the mixture was burned in an air atmosphere. The record of the electrical conductivity of this flame was the same as that of the usual hydrogen flame ionization detertor.A wire mesh screen previously treated with a solution of an alkali metal hydroxide or salt was mounted above the flame. This screen served two purposes: it defined the volume of ga. 7 of which the electrical conductivity was to he measured and it acted as a potential source of alkali metal vapor. When a compound containing halogen or phosphorus was burned in the flame, the rate of release of alkali metal vapor from the heated screen was increased. Since this vapor was carried upward in the flowing gas, it did not enter the flame and did not change its electrical conductivity. A second hydrogen flame was mounted just above the screen. The metal vapor released from the screen ...