T. S. Danowski

Crystalline l-amino-acid oxidase from the soluble fraction of rat kidney cells

Abstract 1. 1. l - Amino - acid oxidase ( l - amino - acid:O 2 oxidoreductase (deaminating), EC 1.4.3.2) has been crystallized from the soluble fraction of rat-kidney cells and compared with crystalline l - amino - acid oxidase isolated earlier from extracts of rat-kidney mitochondria. The immunochemical and physicochemical properties of the crystalline enzyme from the soluble fraction are essentially the same as those of crystalline mitochondrial oxidase. 2. 2. l - Amino - acid oxidase is present in the soluble fraction of rat-kidney cells in concentrations some 4-fold greater than those isolated from mitochondrial extracts. 3. 3. Crystalline l - amino - acid oxidase obtained from either the soluble fraction or from mitochondrial extracts is completely precipitable with antienzyme and the resulting enzyme-antienzyme complex shows full oxidase activity.

Increases in Serum Thyroxin during Uncomplicated Pregnancy.

Summary and Conclusions The rises in protein-bound iodine which usually occur in uncomplicated pregnancy in human subjects are associated with an increase in the thyroxin fraction of the protein-bound iodine. The authors are indebted to Mr. Carroll S. Weil for assistance in the statistical evaluation of these data.

Is pregnancy followed by relative hypothyroidism

Abstract The finding of lower serum protein-bound iodine values during the first year post partum raises the possibility that an interval of relative hypothyroidism follows upon normal pregnancy.

[218c] l-Amino acid oxidase (rat kidney)☆☆☆

Publisher Summary This chapter discusses the methods of preparation of L-Amino Acid Oxidase (Rat Kidney). One unit of enzyme catalyzes the formation of 1 millimicromole of α-ketoisocaproate per hour from L-leucine. Protein content can be determined by phenol-biuret with bovine serum albumin as the standard. The enzyme can be purified and crystallized from the mitochondria and from the soluble fraction of rat kidney cells by the procedure given below. The soluble fraction (original supernatant from kidney cells) is obtained by differential centrifugation (after isolation of mitochondria) and used for the next step of the purification without further treatment. Crystalline L-amino acid oxidase obtained from either mitochondrial extracts or from soluble fractions is completely precipitable by an excess of anti-enzyme obtained from a rabbit previously immunized with mitochondrial L-amino acid oxidase. The resulting enzyme-antibody complex still manifests full oxidase activity. Subfractionation of the rough mitochondrial fraction from rat kidney by means of density gradient centrifugation has confirmed that L-amino acid oxidase is located in the peroxisomes rather than in mitochondria.

Fecal electrolytes and nitrogen during cortisone or ACTH therapy.

Summary and conclusions 1. Cortisone and adrenocorticotropic hormone did not produce any characteristic change in fecal electrolytes and nitrogen in a group of miscellaneous patients maintained on milk formulae of restricted or unrestricted sodium content. 2. Data have been presented on the fecal excretion of sodium, potassium, chloride, and nitrogen during maintenance of such patients on a whole milk or sodium-free milk formula.

Enzymatic Determination of Small Quantities of Hydrogen Peroxide

Summary Two reactions, (a) H2O2 with ethanol in the presence of an excess of catalase, and (b) acetaldehyde with NADH in the presence of yeast alcohol dehydrogenase have been employed in assays of H2O2 during the oxidation of a suitable substrate with an H2O2 generating enzyme. A method is described for the accurate measurement of minute amounts of H2O2. L-α-hydroxy acid oxidase from rat liver, L-amino acid oxidase from rat kidney, and uric acid oxidase from Candida utilis were used as H2O2 generating enzymes. The amount of H2O2 produced was determined photometrically from the change in optical density at 340 mμ. Recoveries with this method exceeded 80%.

Decreased or Absent ACTH-Like Activity of Blocked Synthetic Tricosapeptide.

Summary Substitution of acetyl for hydrogen in the NH2 group of the N-terminal serine, NH2 for OH” in the carboxyl of glutamine in position 5, and formyl for an amino hydrogen of lysine in positions 11, 15, 16, and 21 decreases or eliminates the ACTH-like activity of a synthetic tricosapeptide which duplicates the first 23 amino acids of naturally occurring ACTH.

Potassium studies in pediatric diseases (pyloric stenosis, renal failure, and diabetic acidosis).

The attention of the clinical investigator and the concern of the pediatrician have increasingly turned to changes in cell constituents occurring in illness and disease, This in no wise means of course that all questions relevant to the other major component of body fluid, i. e. the extracellular water and solutes, have been resolved. It does indicate however that currently all of the wihter and electrolyte subdivisions of the body, outside and inside of cells, are being critically evaluated in bedside situations. In many ways this is not a simple task, since at present it is usually possible only to define changes in cells by indirect evidence rather than direct analysis. This involves not only the measurenient of various serum components, but necessitates also a careful accounting of :dl intake and outpat. Studies along these lines are yielding clinically applicable information. Our interests have centered about the electrolyte, nitrogen, carbohydrate and water changes in vomiting infants, in children with far advanced rend insufficiency

Purification of Thyroid Hormone-Transaminase from Rat Kidney Mitochondria.

Summary Crude transaminase from extracts of rat kidney mitochondria which catalyze the deamination of thyroxine, triiodothyronine and diiodotyrosine was purified by means of a DEAE cellulose column. The elution pattern suggests that the deamination of these three iodinated compounds is effected by one transaminase. Column treatment produced a 3-fold increase in the enzyme.

Effect of Cortisone upon Chemical Composition of Allantoic Fluid of the Chick Embryo.

Summary 1. The observed rise in sodium and the decrease in potassium in the allantois fluid of chick embryos treated with cortisone are the reverse of the reported changes in the urine of human subjects receiving this steroid, and resemble those seen in adrenal insufficiency. 2. The increased chloride and sugar levels in the fluid of the allantois following therapy with the higher dosages of cortisone resemble directionally the renal effects of cortisone in man.