Lymphopenia and lymphocyte transformation in alcoholics.

The basis of peripheral blood lymphopenia observed in patients with chronic alcoholism and liver disease was investigated by examining the effect of sera of these patients on in vitro transformation of normal human peripheral blood lymphocytes. A positive correlation was demonstrated between the serum inhibition of phytohaemagglutinin- and pokeweed mitogen-induced transformation and the degree of lymphopenia. Thus serum factors may contribute to the observed lymphopenia by inhibiting lymphocyte production in vivo.

Enzyme reactions of ATP studied by positional isotope exchange.

Reversible gamma-PO3 transfer in ATP reactions can be recognized by exchange of 18O from the beta,gamma-bridge position to the beta-P-nonbridge positions: (see article). Such intramolecular exchange is less demanding for the detection of the bond cleavage than the usual ATP:ADP isotope exchange because it does not require dissociation of bound ADP from the intermediate complex. Acyl phosphate intermediates are indicated for the glutamine synthetase and carbamyl-P synthetase reactions by their extreme requirements for glutamate and bicarbonate, respectively, for positional oxygen exchange.

Mechanism for oxygen exchange in the chloroplast photophosphorylation system.

The oxygen exchange that occurs between water and the gamma-PO3 of ATP in light-activated chloroplast lamellae was found to proceed with close to full equilibration of the oxygens before ATP returned to the medium. This is in contrast to the entry of approximately one water oxygen when ATP is synthesized from ADP and P1 in the same system. In the latter case, the limitation is kinetic, however, not steric, as shown by the presence of some molecules containing more than one water-derived oxygen in the gamma-PO3.

Studies on the mechanism of Escherichia coli glucosamine-6-phosphate isomerase.

Escherichia coli glucosamine-6-phosphate isomerase is specific for removal of the 1-pro-R hydrogen of fructose 6-phosphate (fructose-6-P). The conversion of [2-3H]glucosamine-6-P to fructose-6-P plus ammonia is accompanied by 99% exchange of tritium with water and 0.6% transfer to C-1 of fructose-6-P.

Specificity of fructose-1, 6-P2 aldolase (muscle) and partition of the enzyme among catalytic intermediates in the steady state.

Others have concluded that beta-fructose 1, 6-bisphosphate is a substrate for muscle aldolase on the basis of rapid kinetic measurements. In view of new data showing excellent aldol cleavage of an analog of the keto form and a very high rate of spontaneous ring opening, Midelfort et al. (Midelfort, C.

A stereochemical method for detection of ATP terminal phosphate transfer in enzymatic reactions. Glutamine synthetase.

An isotope scrambling method is described for the detection of transient [Enz:ADP:P-X] formation from [18O]ATP in ATP-coupled enzyme reactions. The method makes use of torsional symmetry of the newly formed (see article) group in ADP. [18 O]ATP labeled in the betagama bridge oxygen was incubated with enzyme and reversible cleavage of the PbetaO -- Pgamma bond was detected by the appearance of 18O in the beta nonbridge oxygens of the ATP pool.

Kinetic competence of a phosphoryl enzyme intermediate in the glucose-1,6-p2 synthase-catalyzed reaction. Purification, properties, and kinetic studies.

Glucose-1,6-P2 synthase of beef brain which catalyzes the formation of glucose-1,6-P2 and glycerate-3-P from glycerate-1,3-P2 and glucose-1-P has been purified 700-fold with an overall recovery of 19%. The purification procedure involves an ammonium sulfate fractionation of the crude extract, DE52 and hydroxylapatite column chromatography and isoelectric focusing. The isolated enzyme appears to be homogeneous by sodium dodecyl sulfate gel electrophoresis.

Fructose 1,6-bisphosphate: isomeric composition, kinetics, and substrate specificity for the aldolases.

13C NMR shows fructose 6-phosphate and fructose 1,6-bisphosphate to contain respectively 4.1 and 2.0% keto isomer at room temperature.

Intermolecular tritium transfer in the transcarboxylase reaction.

Transfer of tritium from [3-3H]pyruvate into propionyl-CoA is found during the reaction of transcarboxylase: Methylmalonyl-CoA + pyruvate leads to oxalacetate + propionyl-CoA. About 5% of the tritium counts that are labilized in the reaction are found in a position of the propionate that exchanges rapidly with water in the presence of transcarboxylase. Transfer from [2-3H]propionate of propionyl-CoA to pyruvate is real but only about one-tenth as great.

Oxalacetate decarboxylase activity in muscle is due to pyruvate kinase.

The enzyme from cod fish muscle that catalyzes the irreversible decarboxylation of oxalacetate and is homogeneous by several criteria contains very significant pyruvate kinase activity. For every unit of decarboxylase activity (0.90 unit/mg) there are 235 units of pyruvate kinase activity (212 units/mg).

Studies on the mechanism and stereochemical properties of the oxalacetate decarboxylase activity of pyruvate kinase.

When cod fish muscle oxalacetate decarboxylase catalyzes the decarboxylation of oxalacetate in the presence of NaBH4, L-lactate results from the reduction of enzyme-bound pyruvate. However, D-lactate results when borohydride reduces the binary enzyme-pyruvate complex formed by adding pyruvate from solution, as reported by others. This observation suggests that there are alternate mechanisms for reduction that are either kinetically or sterically determined for the E-pyruvate forms produced in the two directions.

[Intrauterine gas gangrene in the 37th week of pregnancy].

A report is given on an infection of intrauterine gas gangrene of stage 2 according to Dieminger (Tumpania uteri) in the 37th week of pregnancy which turned out well. The clinical progress of gas gangrene is discussed. The abstention from a caesarian section by reason of indication of the child with suspicion of a severe intrauterine infection, the vaginal delivery which was forced subsequently, the prevailingly prophylactic administration of antibiotics, and the largely initiated infusion and transfusion therapy have in a high degree determined the positive end of the disease.

A specific enzyme for glucose 1,6-bisphosphate synthesis.

The reaction: glycerate-1,3-P2 PLUS GLUCOSE-1-P YIELDS TO GLUCOSE-1,6-P2 plus glycerate-P is catalyzed by a distinct enzyme of mouse brain. A divalent metal requirement was shown when the enzyme was treated with imidazole and EDTA. Mg2+, Mn2+, Ca2+, Zn2+, Ni2+, Co2+, and Cd2+ were quite effective cofactors.