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Biomedical subjects

E Beutler

Publications and source records attributed to E Beutler.

At least 451 records · Page 25Linked to original sources
PubMed1975

Pyridoxal kinase: decreased activity in red blood cells of Afro-Americans.

The mean pyridoxal kinase activity in red blood cells of American blacks was approximately 50 percent lower than that of American whites. Lymphocytes, granulocytes, and cultured skin fibroblasts from black and white donors contained identical pyridoxal kinase activity. The pyridoxal kinase of blacks was indistinguishable from that of whites with respect to heat stability, chromatographic mobility on microgranular diethylaminoethyl cellulose, Michaelis-Menten constant for pyridoxine, and susceptibility to inhibition by 4-deoxypyridoxine. The difference of the activity of this enzyme in whites and in blacks is much greater than any previously observed biochemical difference between the races.

Adult↗
PubMed1975

Redesigned apparatus for anaerobic measurement of blood pH at low temperatures.

A newly designed apparatus for anaerobic measurement of blood pH at low temperatures is presented. This apparatus features a larger glass electrode surface area, which is necessary to overcome the increased resistance of the glass as blood pH determinations at 0-15 C. are undertaken. Utilization of this equipment has confirmed the deltapH per degree C. of whole blood to be 0.0156, while intracellular pH of blood has a deltapH per degree C. of 0.0165.

Acid-Base Equilibrium↗
PubMed1975

Placental acid hydrolase purification on concanavalin A-sepharose.

Crude human placental extract was chromatographed on concanavalin A-Sepharose. Using a single procedure, 20- to over 300-fold purification of six acid glycohydrolases was achieved, in most cases with a good yield. Improved yield of individual enzymes could be achieved by modifications of the method of elution. The capacity of concanavalin A-Sepharose to bind glycohydrolases from placenta was very large, and will provice a useful procedure for the large-scale purification of the human enzymes.

Chromatography↗
PubMed1975

Ethnic variation in red cell glutathione peroxidase activity.

Glutathione peroxidase activity was measured in blood and cultured fibroblasts from healthy persons of several different population groups. Individuals of Jewish ancestry and others of Mediterranean origin were found to manifest a decrease of red cell but not of leukocyte or fibroblast enzyme activity. Oriental populations differed in that the scatter in red cell enzyme activity was significantly lower than in Occidental populations. The erythrocyte enzyme of individuals with low activity was found to be less stable to heating than was the enzyme from persons with high activity. As a possible explanation for these data, a provisional genetic model is presented: a low GSH Px allele with a frequency of 0.556 in the Jewish population and of only 0.181 in the United States-Northern European population. Our results suggest that an association between GSH Px deficiency and hemolytic anemia need not represent a cause-and-effect relationship.

Africa↗
PubMed1975

Active transport of GSSG from reconstituted erythrocyte ghosts.

Human erythrocyte ghosts were loaded with 35S-labeled GSSG and with a sucrose marker, and the transport of GSSG to the suspending medium was studied. GSSG transport from ghosts occurred only when ATP was also present in the ghosts, proceeded against a concentration gradient, and was inhibited by fluoride. The rate of transport was dependent upon the intracellular concentration of GSSG. The relationship between GSSG concentration and rate of transport was sigmoidal. Half-maximal transport was observed at a GSSG concentration of approximately 9.6mM. The maximal velocity was estimated to be in the range of 0.27 umole GSSG per ml of ghosts per hr. These data suggest that the rate of GSSG transport a physiologic concentrations of GSSG is not sufficiently rapid to account for the turnover of glutathione by red cells. It seems more likely that the GSSG transport system serves an emergency function of erythrocytes.

Adenosine Triphosphate↗
PubMed1975

The sorbitol-oxidizing enzyme of red blood cells.

The sorbitol-oxidizing enzyme of human erythrocytes has been partially purified and characterized. Its kinetic characteristics were found to be similar to the sorbitol dehydrogenase of sheep liver and the DPN-xyluloxe dehydrogenase which have been isolated from sheep liver and guinea pig liver, respectively. Although this enzyme is able to oxidize sorbitol relatively efficiently, it has very little activity toward dulcitol, and therefore cannot account for the high K-m pathway of methemoglobin reduction by galactose.

Alcohol Oxidoreductases↗
PubMed1975

The effect of carbon monoxide on red cell life span in sickle cell disease.

Carbon monoxide at a concentration of 1000-2000 ppm was administered to sickle cell disease patients. In each of two patients, one 51Cr red cell survival study was carried out before CO administration, and a second study was initiated a few days before CO administration was started. In both, significant prolongation of red cell survival was observed, suggesting that the rheologic properties of sickle cells were favorably influenced in vivo. The administration of carbon monoxide is not recommended as a treatment for sickle cell disease. However, further trials would seem to be justified if conducted under carefully controlled conditions.

Adolescent↗
PubMed1975

Nonenzymatic conversion of human hexosaminidase A.

Incubation of purified hexosaminidase A with merthiolate, parahydroxymercuribenzoic acid, or silver ions resulted in the formation of an enzyme which was identical, in all respects tested, with hexosaminidase B. Its electrophoretic mobility was identical to hexasaminidase B at three different pH levels. Its chromatographic properties, thermostability, and immunologic reactivity with specific anti-hexosaminidase A and anti-hexosaminidase B antisera were indistinguishable from hexosaminidase B. Conversion could be prevented by GSH but was not reversed by GSH once it had occurred. Conversion of hexosaminidase A to hexosaminindase B was accompanied by the appearance of an electrophoretically rapid, catalytically inactive protein. Hexosaminidase B, itself, was unaltered by incubation with merthiolate. These findings support a previously proposed model of hexosaminidase structure in which hexosaminidase A is (alphabeta)3 and hexosamindase B is (betabeta)2. On treatment of hexosaminidase A with merthiolate and other converting agents alpha and beta subunits are presumably dissociated and they reassociate as (betabeta)3, that is, hexosaminidase B. The expected free or polymerized catalytically inactive, alpha chains are detected on acrylamide gel electrophoresis. We suggest that the catalytic site of human hexosaminidase may be present only on the beta subunit and that the alpha subunit influences the substrate specificity of the enzyme, particularly as directed toward GM2.

Chromatography↗
PubMed1975

Hexosaminidase isozyme in type O Gm2 gangliosidosis (Sandhoff-Jatzkewitz disease).

The residual enzyme of the fibroblasts of a child with homozygous type 0 GM2 gangliosidosis (Sandhoff-Jatzkewitz disease) has been found to correspond with a minor fraction of enzyme which can be isolated from normal fibroblasts by repeated chromatography. This enzyme is designated as hexosaminidase (hex) S. It reacts with antiserum prepared against homogeneous hex A but not with serum prepared against homogeneous hex B. These findings support our previously described model of the relationship between hex A and hex G: hex A has the structure (alpha beta)3, while hex B is (beta)6. Type B GM2 gangliosidosis (Tay-Sachs disease) is the alpha- mutation, while type 0 GM2 gangliosidosis (Sandhoff-Jatzkewitz disease) is the beta- mutation. In the absence of normal beta subunits there is increased polymerization of alpha subunits forming hex S, which probably has a structure of (alpha)6. A parallel between the thalassemias and GM2 gangliosidosis is evident: deficiency of one of the chains of which the protein is composed leads to an excess of polymers comprised of the other chains. In type B GM2 gangliosidosis, the excess of beta chanis leads to increased amounts of hex B beta)6; in type 0 GM2 gangliosidosis, the excess of alpha chains leads to formation of increased amounts of the alpha chain polymer, hex S.

Antigens↗