Perchloric Acid-soluble Fraction Research Articles

Immunoelektrophorese der perchlorsäurelöslichen serumproteine

Immunoelectrophoretic pictures of the perchloric acid-soluble fraction of serum proteins were investigated in 20 healthy persons and in 20 patients with rheumatoid arthritis. 3–5 arcs were found in normal sera and 5–7 arcs in pathological specimens. The number of arcs in the immunoelectropherogram was independent of the total amount of the perchloric acid-soluble proteins, estimated as the MPT-value according to Winzler. In only one case was an abnormal arc seen, probably identical with the prealbumin ϱ 2. The remaining immunoelectrophoretic pictures of patients with rheumatoid arthritis showed the same arcs as those of healthy persons. The increase in the number of arcs in pathological samples is probably due to an increased protein solubility caused by inflammatory dysproteinaemia. The term “dys-α-globulinaemia” is proposed, to define qualitative changes of the constituents of the perchloric acid-soluble protein fraction without greater differences of its total level.

BIOSYNTHESIS OF NUCLEOTIDES IN WHEAT. II. PYRIMIDINES FROM C14-LABELLED COMPOUNDS.

Aspartate-U-C14and uracil-2-C14were fed to wheat leaves and embryos respectively. The alcohol-soluble and perchloric acid soluble fractions were treated with Norit A, and the Norit eluates were subjected to paper chromatography to identify the pyrimidines and derivatives synthesized from the labelled compounds. Both compounds were found to be precursors of pyrimidine nucleotides. The results are discussed in relation to recent views on the pathway of pyrimidine nucleotide synthesis in plants.

Effects of crude pancreatic elastase on serum haptoglobin

Elastase injected intravenously in rabbits produces up to a 7-fold rise in serum haptoglobin and a 2-fold rise in seromucoid (perchloric acid-soluble fraction). Unlike intravenous papain, elastase produces no rise in serum uronic acid, although in vitro cartilage is degraded by it. In vitro incubation of haptoglobin-rich sera with elastase gives rapid inactivation of haptoglobin, with a rise in perchloro-soluble protein, hexose and sialic acid. Thus, in vivo proteolysis of serum mucopolysaccharide-protein complexes and lipoproteins would not explain the increase in haptoglobin, but could be in part responsible for the seromucoid increase and for the observed lipemia. Failure to liberate uronic acid may be related to rapid clearance or inhibition of the enzyme, or to failure to reach cartilage sites.

Immunoelectrophoretic studies of the beta1-haem-binding globulin (haemopexin) in hereditary haemolytic disorders.

NEALE et al.1 have demonstrated by paper electrophoresis a haem-binding globulin in the β-globulin fraction of human serum. Since then, several investigators examined this protein2–6, which was identified by immunoelectrophoresis with β1-B-globulin and called haemopexin7. On starch-gel electrophoresis the haem-binding protein was found to migrate with the fast α2-globulins8,9. Haemopexin is present in the perchloric acid-soluble fraction of serum7,10 from which Schultze et al.11 obtained a highly purified preparation by combined ammonium sulphate precipitation and zone electrophoresis. Haemopexin is a glycoprotein containing approximately 20 per cent carbohydrate and has a sedimentation rate of 4.8S corresponding to a molecular weight of approximately 80,000. The purified protein has a binding capacity of 15–20 mols haemin per mol haemopexin; evidence for binding of haemoglobin or cytochrome c could not be obtained. The haemin binding capacity of normal human serum is approximately 10 mg/100 ml. (refs. 2 and 9).

Synthesis of canine seromucoid before and after total hepatectomy.

The incorporation rate of S35 DL-methionine into the perchloric acid-soluble (seromucoid) fraction of serum was studied in the same four dogs before and after a one-stage total hepatectomy. This incorporation rate was used as an index of seromucoid synthesis. In all dogs before hepatectomy there was a rapid incorporation rate reaching a maximum synthesis in approximately 6 hr after injection. After hepatectomy the average incorporation rate was reduced to about one-third of prehepatectomy levels. It is concluded that in the dog most of the perchloric acid-soluble (seromucoid) fraction is of hepatic origin whereas a smaller part is synthesized by extrahepatic tissues.

Orosomucoid in schizophrenia.

OROSOMUCOID, a glycoprotein extremely rich in carbohydrate, is the principal constituent of the perchloric acid-soluble seromucoid fraction of human serum1. In contrast to the seromucoid fraction which contains several proteins and represents more than one biological entity, orosomucoid is homogeneous and behaves as a single protein. With the production of specific chicken antiorosomucoid sera2,3, it has become possible to investigate the clinical significance of orosomucoid. Interest in doing so arises from the fact that elevations of seromucoid and total serum glycoprotein-levels occur in a number of diseases; for example, in malignancy, tuberculosis, rheumatoid arthritis, and multiple sclerosis4. Elevations in this chemically defined group of proteins also occur in response to a wide range of non-specific stressors such as fractures, epinephrine injection, and burns5.

Properties of crystalline hexokinase from yeast. I. Analyses for possible Co-factors

Yeast hexokinase which is fully active contains no biotin as assayed with Neurospora crassa and Saccharomyces cerevisiae, 139, does not possess a readily demonstrable prosthetic group, and is not a metalloprotein. A perchloric acid-soluble fraction which remains associated with the enzyme is described.

Influences of proteolytic enzymes on parotin. III. Rate of digestion of parotin by trypsin and chymotrypsin. (Studies on the physiological chemistry of the salivary glands. LI).

The ultraviolet absorption of the perchloric acid-soluble fraction in digested parotin by trypsin and chymotrypsin rapidly increased within 1hr. and showed the maximum rate of digestion after 3hrs. of incubation. At the ultraviolet estimation, the use of perchloric acid as protein-precipitating reagent was proved more preferable than trichloroacetic acid.

Influences of proteolytic enzymes on parotin. V. Influence of chymotrypsin on parotin. (Studies on the physiological chemistry of the salivary glands. LII).

Both the calcium activity and the leukocyte activity of parotin were relatively resistant to the action of chymotrypsin, and remained even after 7hrs. of digestion. The ultraviolet absorption of the perchloric acid-soluble fraction in digested parotin by chymotrypsin rapidly increased within 1hr. owever the shift of the isoelectric point of parotin as seen in the tryptic digestion was not seen by the chymotryptic digestion.The following 3 fractions were separated from the parotin digested for 3 hrs.; the precipitate yielded at its isoelectric point, pH 5.4, an insoluble fraction in 80% concentration of acetone, and a soluble fraction in this acetone solution.Among these 3 fractions only the first, pH 5.4-precipitate, showed all biological activities.

The measurement, physiological importance and control of proteolytic enzyme inhibitors

Inhibitors are present in mammalian plasma to certain enzyme systems, and the titre of these inhibitors has in many instances been shown to be under direct hormone control. Curtain electrophoresis under controlled conditions allows separation and subsequent identification of these inhibitors, and their concentration in serum can be estimated. Immediate and stoichiometric inhibition of the hydrolytic action of chymotrypsin is brought about by serum inhibitors, but splitting of carbohydrate/protein bonds takés place long after the inhibition to proteolysis is maximal, leading both to increase of perchloric acid soluble phosphotnngstic acid insoluble serum fractions, and increase of serum sialic acid. It would appear that this action of chymotrypsin is distinct from the proteolytic action in that it is governed by the law of mass action, and is facultatively reversible. The measurement and significance of this is discussed.

Cholesterol in seromucoid fraction of normal and pathologic sera.

Summary1. A fairly fixed amount of free cholesterol and cholesterol esters is found in the perchloric acid soluble (seromucoid) fraction of human serum. Phenomena of co-precipitation or of adsorption are probably responsible for this finding. 2. Seromucoid fraction, total serum cholesterol, cholesterol found in the seromucoid fraction were studied quantitatively in pathologic sera obtained from patients with lymphoma, disseminated malignancies, acute leukemia and from selected patients with liver disease. Seromucoid fraction was elevated in all diseases. Cholesterol found in the seromucoid fraction was relatively increased in sera of patients with lymphomas and metastatic carcinomas; relatively or absolutely decreased in acute leukemias and liver disease. 3. The significance of these findings consisted in the indication of possible effects of perchloric acid on cholesterol-containing components of serum. Such effects seemed to vary from normal to pathologic conditions, thus suggesting the possible future ...