Effects of halide ions on porcine kidney catalase

The inactivating effects of halide ions on porcine kidney catalase were investigated. It was found that the inactivation of catalase was dependent on incubation time with halides and on their concentrations: the addition of 2 M NaCl reduced the activity to 18% of the original level, whereas the same extent of inactivation was obtained in the presence of 0.1 M NaF. Removal of excess halide ions by dialysis resulted in good recovery of enzyme activity for all halides examined except for KI. Additions of halide ions to catalase solution caused subtle but evident alterations in the absorption and CD spectra. We could detect clear difference spectra between the salt-treated and native catalase solutions. These difference spectra showed halide concentration dependence with an evident isosbestic point. From these changes and also changes in CD spectra, we deduced that fluoride, chloride, and bromide ions can bind with heme iron of the catalase molecule as ligands to form stable catalase-halide complexes, but iodide ions showed a different reactivity with catalase from other halides and may cause gross alteration in the structure or conformation of catalase. Dissociation constants (Kd) were estimated to be 2.5, 0.23, and 26 M for chloride, fluoride, and bromide complexes with catalase, respectively, and there is no heme-heme interaction during formation of the catalase-halide complexes as estimated from the Hill plot.

Spontaneously acquired factor VIII inhibitor in a 7-year-old girl

The youngest case with spontaneously acquired inhibitor to factor VIII is reported. A 7-year-old girl without any previous disorders presented with a hemarthrosis in the left knee and developed a rapidly expanding hematoma on the right arm, shoulder and chest after an initial infusion of factor VIII concentrate (1,000 units). Circulating antifactor VIII antibody was detected. Her coagulopathy was successfully managed with an additional massive infusion of factor VIII concentrate (7,500 units) and combination therapy of prednisolone and cyclophosphamide.

Impaired lactate production by skeletal muscle with anaerobic exercise in patients with chronic renal failure. A possible consequence of defective glycolysis in skeletal muscle

The lactate concentration in antecubital venous blood was determined in 33 patients before and after ischemic forearm exercise. Before exercise, there wa no significant difference in serum lactate level between uremic patients and controls. However, after ischemic exercise the means serum lactate level in uremic patients was significantly lower than that of controls. The results may lead to the conclusion that uremic patients have a markedly reduced ability to form lactate with anaerobic exercise probably due to inhibition of glycolytic enzymes of skeletal muscle.

Serum inhibitory factor for guinea pig macrophage and neutrophil chemotaxis found in cancer patients

The effect of sera from 107 patients with gastrointestinal cancer on macrophage chemotaxis was studied using a modified Boyden chamber technique. A macrophage chemotactic inhibitory factor (CIF) was found in sera of advanced cancer patients. The CIF activity was significantly stage-related, and increased especially in patients with negative cutaneous responsiveness in purified protein derivative, dinitrochlorobenzene and keyhole limpet hemocyanin skin tests, and with low circulating T-lymphocyte levels. In addition, the CIF was found to suppress neutrophil as well as macrophage chemotaxis. suppress neutrophil as well as macrophage chemotaxis. The mode of action and the characteristics of the CIF were investigated, and the following results were obtained. (1) The CIF directly interacted with macrophages and neutrophils and suppressed their chemotactic activities without apparent cytotoxic effect on these cells. (2) On Pevikon block electrophoresis, the CIF activity was most prominent in the alpha-globulin region, although considerable heterogeneity and broadness of the CIF bands were observed. (3) Dialysis and lyophilization had no effects on the CIF activity. On heating at 56 degree for 30 min, the CIF activity seemed to be decreased. This study indicates that CIF in cancer patients may be detrimental to the host immune defense against tumor growth by producing defects of macrophage and neutrophil chemotaxis in vivo.

On the acid denaturation of porcine erythrocyte catalase in relation to its subunit structure

Porcine erythrocyte catalase [EC 1.11.1.6] (molecular weight, ca. 250,000) was found to dissociate partially between pH 3.5 and 3.0 and completely below pH 3.0 into two presumably identical 1/2-sized subunits (molecular weight, 112,000) as estimated by ultracentrifugal analyses. This dissociation was accompanied by a marked change in hydrodynamic properties; the sedimentation coefficient decreased from about 11S to 4S. This acid denaturation also resulted in complete loss of enzyme activity and disappearance of absorption bands characteristic of heme protein, in particular, a shift of the Soret band from 405 nm to a small and broad band at 375 nm. The change in enzyme activity correlated well with that of the Soret band, depending on the denaturation time and pH used. Reversible recovery of enzyme activity was not detected below pH 3.1 after 2 h denaturation. The pH dependence of alpha-helical content estimated from the CD intensity at 222 nm also correlated well with that of enzyme activity. The rate constants of initial reaction of acid denaturation at several pHs were determined by following the changes in the Soret band with time, since the changes showed an isosbestic point at 384 nm. The results revealed that the first-order rate constant at pH 3.0 was 45 times larger than that at pH 3.4, indicating that the rate of acid denaturation increased rapidly within a narrow acidic pH range. The temperature dependence of the denaturation rate was also measured and the activation energy for the acid denaturation was found to be 76.3 kcal/mol from an Arrhenius plot.

Lipoprotein abnormalities in the pathogenesis of cerebral infarction and transient ischemic attack

HDL-cholesterol levels were determined by a heparin-Ca precipitation method in 89 survivors of cerebral infarction (CI) (75 males, 14 females) and 14 patients with transient ischemic attacks (TIA) (8 males, 6 females). The mean values of HDL-cholesterol concentration and HDL:LDL-cholesterol ratio for both sexes of CI patients were significantly lower than those of the healthy controls (37 males, 14 females). These values for CI patients were significantly lower than in patients with various diseases excluding cardiovascular disease, hepatic disease, hyperlipidemia, diabetes mellitus and degenerative disorders of the nervous system (46 males, 43 females). In patients with TIA, these differences were statistically significant only for men. Based on the patient's history, clinical signs and symptoms and the findings of computerized tomography and 4-vessel angiography, male CI patients were divided into 2 sub-groups, CI believed to be in the distribution of a perforating artery and CI in the distribution of a cortical artery; it was found that the HDL-cholesterol level and HDL:LDL-cholesterol ratio were significantly lower in the cortical artery group than in the perforating artery group, suggesting that these lipoprotein abnormalities may play a part in the pathogenesis of CI, particularly of the cortical artery area infarction.

Subcellular distribution and characterization of porcine kidney catalase

Subcellular distribution of catalase for porcine kidney was analyzed by differential centrifugation of kidney homogenate. The specific activity of catalase was the highest in light mitochondrial fraction, followed by mitochondrial, cytosolic, nuclear, and microsomal fractions. However, about a half of the total activity was found in supernatant (cytosol) fraction and the other half was mainly associated with both mitochondrial and light mitochondrial fractions. Osmotic shock using hypotonic solution, 50 mm sodium phosphate buffer (pH 7.0) was found to be most effective for solubilization of particulate-bound catalase. Both particulate and cytosol catalases from porcine kidney were purified by ammonium sulfate fractionation followed by DEAE-cellulose, CM-cellulose, and Sephadex G-100 column chromatographies. The purified enzymes showed two distinct bands, one major and the other minor, on disc gel electrophoresis. Both particulate and cytosol enzymes showed identical molecular weights estimated from disc gel electrophoresis; that of the major component was 219,000 corresponding to native molecule and that of the minor one 421,000. A similar value, 210,000, was also obtained for the major component by gel filtration on a Bio Gel A-1.5 m column. It was inferred that the minor component was formed by dimerization of native molecule caused by formation of disulfide cross-links due to oxidation of SH groups in protein moiety. The particulate and cytosol catalases showed essentially identical molecular characteristics, although a slight difference was detected in stability in guanidine-HCl solution. The effect of NaCl on enzyme activity and optical properties of catalase were also measured.

Inhibitory effect of cadmium on collagenous peptide synthesis of embryonic chick bone in tissue culture

The effect of cadmium (Cd) on bone collagen synthesis was assessed in organ cultures of embryonic femur by measuring the incorporation of [3H]-proline(Pro) into collagenous-digestible protein (CDP) using purified bacterial collagenase. Cd produced a decrease when [3H]Pro ws incorporated in CDP. There was little alteration in the hydroxylation of [3H]Pro to [3H]hydroxyproline(Hyp) in CDP of Cd-treated bone. An accumulation of underhydroxylated collagen and a decrese in the activity of prolyl hydroxylase (EC 1.14.11.2) in Cd-treated bone was not observed. These reslts indicated that the inhibitory effect of Cd on collagen synthesis was largely due to inhibition of collagenous peptide synthesis without inhibition of its hydroxylation.

The interactions of thiol compounds with porcine erythrocyte catalase

The effects of thiol compounds on the conformation of porcine erythrocyte catalase were examined. The thiol compounds showed two types of reactivity with the catalase in terms of changes in absorption spectra. One is characterized by the appearance of a new absorption maximum at 595 nm; this was seen with 2-mercaptoethanol (designated as inactive catalase type I). The other is characterized by new maxima at 535 and 570 nm, and this was seen with reduced glutathione, dithiothreitol, cysteine, and cysteamine (inactive catalase type II). The thiol compounds caused gradual inactivation of catalase, correlating with the enhancement of the absorption maximum at 595 nm or 570 nm. Removal of excess thiol reagents from the reaction mixtures caused partial recovery of activity, which was more marked with inactive catalase type II. Similar reversibility was observed in the absorption, CD and MCD spectra, whereas reversibility was not observed for inactive catalase type I. The MCD spectra suggested conversion of heme groups from a high to a low spin state on incubation with thiols, e.g., reduced glutathione, leading to inactive catalase type II. alpha-Helical conformation of the polypeptide backbone and titratable free SH groups in the catalase molecule were unaffected by all these thiol treatments. It is suggested that "active oxygen" which may be produced on incubation of catalase with thiol compounds, was responsible for the formation of inactive catalase type II.

Effects of divalent cations on thermophilic inorganic pyrophosphatase

Divalent cations were shown to affect the structure and thermostability of thermophilic inorganic pyrophosphatase [pyrophosphate phosphohydrolase EC 3.6.1.1] purified from Bacillus stearothermophilus and thermophilic bacterium PS-3. The properties of the enzymes from the two sources were found to be very similar. The enzymes were very unstable to heart in the absence of divalent cations, being inactivated gradually even at 40 degrees C. However, they became stable to heat denaturation in the presence of Mg2+, between pH 7.8 and 9.0. Similar induced thermostability was detected when Mn2+, Co2+, Ca2+, Cd2+, and ZN2+ were added, though the latter three cations were not essential for enzyme activity. On adding divalent cations, the optical properties such as absorption spectra, fluorescence spectra, and circular dichroism (CD) were changed. Gel filtration and disc electrophoresis revealed that the molecular weight of both enzymes was 5.4 x 10(4) in Tris-SO4 buffer and 11 x 10(4) in Tris-HCL buffer, suggesting monomer-dimer transformation. In the presence of divalent cations in Tris-SO4 fuffer, the enzymes dimerized; this was confirmed by sedimentation velocity measurements. The enzymes in Tris-HCL buffer did not show thermostability unless divalent cations were added. The results in the present study indicate that binding of divalent cations to each enzyme caused some conformational change in the vicinity of aromatic amino acid residues leading to dimerization of the enzyme molecule so that it became thermostable. It was also suggested that histidyl residues play an important role in the thermostability induced by divalent cations on the basis of the pH dependencies of thermostability and CD spectra.

Abnormal lipoprotein appearing in plasma of patients who received a ten percent soybean oil emulsion infusion

In 42 of 43 surgical patients who received a 10% soybeam oil emulsion (Intralipid), abnormal lipoprotein was detected in their plasma 1 to 2 days after the initial Intralipid infusion. This abnormal lipoprotein was proven to appear as a result of the infusion of soybean oil emulsion regardless of the patient's original diseases, age, sex, liver function, or concomitantly administered solutions. In addition, this abnormal -ipoprotein was found to have various similarities to lipoprotein-X (LP-X) which is found in plasma from patients with obstructive jaundice or familial lecithin:cholesterol acyltransferase deficiency. Therefore, this abnormal lipoprotein was tentatively named LP-X--like substance (LP-X-LS). A comparison of the properties of LP-X and LP-X-LS was performed and the following results were obtained: (1) LP-X-LS migrated toward the cathode on Bacto-Agar gel electrophoresis similarly to LP-X; (2) the stability of LP-X and LP-X-LS against heating and freezing were almost equal under various conditions; (3) LP-X-LS could be absorbed by anti--LP-X serum; (4) LP-X-LS existed in low density fraction (d = 1.063) separated by ultracentrifugation from plasma; (5) electron microscopic study of low-density lipoprotein particles from LP-X-LS positive plasma revealed that LP-X-LS had a similar ultrastructure to LP-X. From these results it is suggested that LP-X-LS is an abnormal lipoprotein quite similar to LP-X.

Age-related change in the reducible cross-link of human skin and aorta collagens

Age-related changes in the reducible cross-links of soluble and insoluble collagens from the human skin and aorta were evaluated. Histidinohydroxymerodemosine decreased with age up to the fifth decade and then remained constant in the insoluble skin collagen but could not be detected in the insoluble aorta collagen. Dihydroxylysinonorleucine could be observed, if in a small amount, in the insoluble aorta collagen but not in both the soluble and insoluble skin collagens. Hydroxylysinonorleucine seemed to be present in only a small amount, although coeluting unknown substances made it difficult to evaluate correctly. Two unknown components decreasing with age were found; the one in the insoluble skin collagen and the other in the insoluble aorta collagen. Difference in reducible cross-link was indicated between the skin and aorta collagens.