David D. Ulmer

The Magnesium-Deficiency Tetany Syndrome in Man

MAGNESIUM is second only to potassium in abundance as an intracellular cation. The whole body of a human adult contains nearly 25 gm.1 The numerous important biochemical reactions dependent upon th...

Optically active metalloprotein chromophores II. Transferrin and conalbumin

Abstract In a previous communication Li et al., 1962 , Ulmer et al., 1962 , Ulmer et al., 1962 we reported the identification of an optically active cadmium-mercaptide chromophore in metallothionein, a protein isolated from horse kidney cortex. This observation suggested that the metal-binding site of metalloproteins may constitute a source of rotatory power in addition to that of protein conformation, the constituent amino acids, and -- when present -- bound prosthetic groups. In this regard, we have now found that the visible absorption bands of the iron complexes of transferrin and conalbumin are optically active. It has been suggested that the properties of the metal-binding sites of these two proteins are remarkably similar (Warner and Weber, 1953; Inman, 1956). Notably, the Cotton effects which appear upon formation of their iron complexes are virtually identical.

Magnetic circular dichroism of non-heme iron proteins☆

Abstract The magnetic circular dichroism (MCD) at 45 kgauss has been determined for a group of non-heme iron proteins. Both transferrin and conalbumin exhibit a single, positive ellipticity band at 330 nm ([θ]M = 560). Oxy- and methemerythrin, spinach and clostridial ferredoxins and rubredoxin all display distinctive multibanded spectra which may reflect such factors as coordination of the metal, its ligands, metal bridging by other atoms, and varying degrees of metalmetal coupling. The MCD spectra of both ferredoxins and rubredoxin undergo dramatic change upon oxidoreduction providing a potential means for relating the electronic structure of the iron to protein function. In contrast to the plant ferredoxins, the magnetic field does not significantly affect the CD spectra of adrenodoxin and putidaredoxin.

Effect of metal binding on the hydrogen-tritium exchange of conalbumin

Abstract 1. 1. The rates of hydrogen-tritium exchange of chicken egg conalbumin and its metal complexes have been studied by the gel-filtration technique7 at pH 8, 4°. 2. 2. Iron-conalbumin retains approx. 50 more tritium atoms than does the apoprotein at all times during the course of exchange; both rapidly and slowly exchanging classes of hydrogen are shown to be affected by metal binding. 3. 3. Manganese- and copper-conalbumin also exchange more slowly than does the apoprotein, but these metals retard exchange less than does iron. 4. 4. The effect of iron on the hydrogen-tritium exchange of human serum transferrin is similar to that observed for conalbumin. 5. 5. These data suggest that the apo- and metalloproteins differ in conformation and that the structure of the latter is more compact.

Automated determination of δ-aminolevulinic acid dehydratase activity in human erythrocytes☆

Abstract An automated assay for the estimation of δ-aminolevulinic acid dehydratase activity in human erythrocytes has been devised. The present design allows the performance of thirteen analyses per hour. Samples are hemolysed by saponin in the flow system. Lateral interaction between consecutive samples is negligible and repeatability of analysis is excellent. The analytical values of the automated and manual procedures correlate strongly. In randomly selected, hospitalized patients the mean value of δ-aminolevulinic acid dehydratase activity is significantly lower than that found in a normal population.

Biophysics of Physiological and Pharmacological Actions: Papers Presented at New York Meeting of the American Association for the Advancement of Science, December 26-28, 1960

This volume consists of 30 papers which were presented in December, 1960, at a symposium sponsored jointly by the American Association for the Advancement of Science, the American Physiological Society, and the Society of General Physiologists. Primary emphasis is given to current concepts of the electrical and ionic events associated with nerve and muscle excitability. Active transport and membrane selectivity in elementary systems such as red blood cells are discussed first; the more complex problems presented by nerves, voluntary striated muscle, cardiac muscle, and smooth muscle are then dealt with successively. Junctional transmission and the contractile mechanism in muscle receive special attention and the probable energy supply for the various activity processes is discussed. The mechanism of action of certain pharmacologic agents is considered in terms of their effect on membranes. Numerous models, conceived in the light of recent experimental data, are presented. Throughout, the illustrations are of good quality.