Limited autolysis of Ca2+-activated neutral protease (CANP) changes its sensitivity to Ca2+ ions

Ca2+-activated neutral protease (CANP) usually requires mM Ca2+ for activation. The sensitivity of CANP to Ca2+ is greatly enhanced by passing it through a casein-Sepharose column in the presence of Ca2+ ions. This conversion is ascribed to autolysis of CANP. The converted enzyme required 40 microM Ca2+ for 50% activation. Various properties of the converted enzyme were very similar to those of CANP-I, recently found in canine heart muscle. Names of "m-CANP" and "mu-CANP" are proposed for CANPs which require mM and microM order Ca2+ for inactivation, respectively.     

Immobilized mitochondrial electron transport particle for NADH determination

Nonphosphorylating electron transport particles (ETP) prepared from beef heart mitochondrion were immobilized in agar gel. The immobilized ETP showed an oxidase activity to both NADH and succinate. The immobilized ETP was reusable. An electrochemical device for the determination of either NADH or succinate was assembled consisting of the membrane-bound ETP and an oxygen probe. The response to succinate was specifically inhibited by the addition of malonate.     

Identification of metabolic model: Citrate production from glucose by Candida lipolytica

The concept of mass balance was used to analyze the metabolic pathways of citrate production by Candida lipolytica from glucose. Specific rates of glucose consumption, citrate and isocitrate productions, carbon dioxide evolution, and cellular syntheses of protein and carbohydrate were observed in an NH₄⁺-limited chemostat culture. These data permitted one to assess the carbon flux in vivo by solving simultaneous carbon balance equations with respect to intermediary metabolite pools in the steady State. Among the three models considered here, model I (which coordinates the pyruvate carboxylation with the tricarboxylic acid cycle, but disregards the glyoxylate cycle) was considered plausible because the carbon flux calculated so far was acceptable. On the other hand, models II and III (which overlook the pyruvate carboxylation and the 2-oxoglutarate dehydrogenation, respectively) were found to be most unlikely because of the unusual flux assessed from these models.     

On the electromotor neurons of both electric organs of Pollimyrus isidori (Mormyridae, Teleostei)

The electromotor neurons (EMNs) of the adult electric organ of Pollimyrus isidori and the "giant neurons" (GNs) found in the more rostral part of the spinal cord were investigated both with light and electron microscopical methods. The two kinds of neuron are more or less similar in size, about 30 microns, and are found in the more dorsal part of the spinal cord. The EMNs show somatosomatic gap junctions, as do the GNs. In addition, chemical synapses could be found between nerve fibres and both types of neurons. Histochemical investigations show that the EMNs and the GNs are both AChE positive. On the basis of the arguments presented in the discussion, we believe that the "giant neurons" are the electromotor neurons of the larval electric organ of Pollimyrus isidori.     

Phosphate permeability in cells ofChlorella ellipsoidea

Summary Active transport of orthophosphate byChlorella ellipsoidea was observed at 25 °C under fluorescent light, about 3 klux. Influx and efflux of phosphate, and extra- and intracellular phosphate concentrations were measured in order to assess phosphate permeability in the cells. The permeability ranged from 10^–3 to 10^–4 mlQ/mg cell min (or 10^–7 to 10^–8cm/sec).     

Amperometric estimation of BOD by using living immobilized yeasts

Summary A microbial electrode consisting of immobilized living whole cells of yeasts, porous membrane and an oxygen electrode was prepared for continuous estimation of biochemical oxygen demand (BOD). Immobilized Trichosporon cutaneum was employed for the microbial electrode sensor for BOD. When a sample solution containing the equivalent amount of glucose and glutamic acid was injected into the sensor system, the current of the electrode decreased markedly with time until steady state was reached. The response time was within 18 min. A linear relationship was observed between the current decrease and the concentration below 41 mg l ^– of glucose and 41 mg l ^– glutamic acid (5-day BOD 60 mg l ^–). The current decrease was reproducible within ± 6% of the relative error when a sample solution containing 27 mg l ^– of glucose and 27 mg l ^– of glutamic acid (5-day BOD 40 mg l ^–) was employed. The microbial electrode sensor was applied to untreated waste waters from a fermentation factory. Good comparative results were obtained between BOD estimated by the microbial electrode and that determined by the conventional 5-day method (regression coefficient was 1.2). Furthermore, the effect of various compounds on BOD estimation was also examined. The current output of the microbial electrode sensor was almost constant for 17 d and 400 tests.     

A new prenyltransferase from Micrococcuslysodeikticus

A new prenyltransferase which catalyzes the synthesis of geranyl pyrophosphate as the only product from dimethylallyl pyrophosphate and isopentenyl pyrophosphate has been separated from other known prenyltransferases from $\text{Micrococcus}\text{lysodeikticus}$. This enzyme fraction is also capable of synthesizing all-$\text{trans}$ geranylgeranyl pyrophosphate from farnesyl pyrophosphate and isopentenyl pyrophosphate though it lacks ability to synthesize farnesyl pyrophosphate.     

Production of an extracellular maltase by thermophilic Bacillus sp. KP 1035.

Production of extracellular maltase was studied with thermophilic Bacillus sp. KP 1035, which was selected as the organism producing the highest levels of maltase. The final enzyme yield was increased by maltose, peptone, and yeast extract but reduced by succinate and fumarate. Maximum enzyme production was achieved at 55 degrees C and at an initial pH of 6.2 to 7.0 on a medium containing 0.3% maltose, 1% peptone, 0.1% meat extract, 0.3% yeast extract, 0.3% KH2PO4, and 0.1% KH2PO4. Maltase was synthesized in cytoplasm and accumulated as a large pool during the logarithmic growth phase, which preceded sporulation. At the end of this phase, the enzyme appeared in the culture broth, and its accumulation increased in parallel with a rise in the extracellular protein level. Maltase was stable for 24 h at 60 degrees C over a pH range of 5.6 to 9.0 and retained 95% of the original activity after treatment for 20 min at 70 degrees C at pH 6.8.     

Fluorimetric assay of sialic acids.

A fluorimetric assay has been developed for sialic acids in which sialic acids react with pyridoxamine to give fluorescent compounds in the presence of zinc ion and pyridine. This assay method is specific for unbound sialic acids and is a simple and sensitive procedure compared with the thiobarbituric acid assay of sialic acids.