Hugo Aebi

Protection of Human Neutrophils by Endogenous Catalase: STUDIES WITH CELLS FROM CATALASE-DEFICIENT INDIVIDUALS

To investigate the importance of catalase as a protecting enzyme against oxidative damage in phagocytic leukocytes, we have tested the functional capacity of neutrophils from two individuals homozygous for Swiss-type acatalasemia and from two individuals heterozygous for this deficiency. In the former cells, 25-30% of residual activity of catalase was present. In the latter cells, the values were close to normal. Chemotaxis towards casein, release of lysosomal enzymes and hydrogen peroxide during phagocytosis of zymosan, and intracellular killing of Staphylococcus aureus were normal in all cells tested. Inhibition of heme enzymes with azide (2 mM) enhanced the respiration and hexose monophosphate shunt activity of normal, but not of homozygous acatalasemic, neutrophils. This indicates that the enhancement in normal cells is, at least in part, due to catalase inhibition. After 15 min preincubation with an H(2)O(2)-generating system (glucose plus glucose oxidase), the respiratory response to zymosan phagocytosis was strongly depressed in the homozygous acatalasemic and in normal, azide-treated neutrophils, but not in normal, untreated cells. Under these conditions, the release of lysosomal enzymes was depressed and that of lactate dehydrogenase enhanced, in catalase-deficient and in catalase-inhibited, but not in normal, neutrophils. During prolonged incubation with the H(2)O(2)-generating system (30-60 min), the reduction level of intracellular glutathione remained high and the hexose monophosphate shunt continued to operate normally in all cells tested. Thus, although the function of neutrophils without catalase activity was depressed by extracellular hydrogen peroxide, the H(2)O(2) degradation via the glutathione redox system remained operative. The results indicate that the glutathione redox system by itself efficiently protects phagocytosing neutrophils against their own oxidative products. During heavy external oxidative stress, however, both catalase and the glutathione redox system are needed for adequate protection.

Activity and stability of catalase in blood and tissues of normal and acatalasemic mice

Catalase activity in blood, liver, and kidney of a mutant strain Csb has been found to be decreased as compared to the level in normal mice. However, the extent of the reduction largely depends on the conditions used for activity determination, in particular, temperature and duration of the incubation period. In liver, this effect is most pronounced, the observed activity in mutants varying between 21 and 85% of the normal level. This dependence on the assay conditions is mainly due to the unusual heat lability of the variant enzyme, which undergoes rapid inactivation when incubated at 37 C.

Separation of catalase and other red cell enzymes from hemoglobin by gel filtration

Es wird über ein einfaches Verfahren zur Abtrennung von Katalase und anderer Enzyme aus konzentriertem Haemolysat mit Hilfe der Gel-Filtration unter Verwendung von Sephadex G-100 berichtet.

Methaemoglobinbildung durch Röntgenstrahlen in normalen und katalasefreien Erythrocyten des Menschen

Methaemoglobin-formation in irradiated human red cells largely depends on catalase activity in either phase of the system. The formation rate is low in normal, but high in acatalatic cells. The latter rate can be lowered to normal by adding 0.1 γ/ml catalase to the suspending medium.

Mangel im Überfluß

Zusammenfassung1. Im Rahmen einer Betrachtung über den gegenwärtigen Stand der Volksernährung werden diejenigen Faktoren diskutiert, welche zu einer Verschlechterung der Schutzstoff-Versorgung (Vitamine, Mineralstoffe, Spurelemente) beigetragen haben:a) Verminderung des Nahrungs- bzw. Kalorienbedarfs (Motorisierung!), b) Abnahme des durchschnittlichen Schutzstoffgehaltes der Nahrung, c) Veränderte Ernährungsgewohnheiten.2. Es werden die zur Verbesserung der Ernährungslage getroffenen Maßnahmen besprochen: a) Verbrauchslenkung durch behördliche Eingriffe in Preisgestaltung und Anpreisung, b) Aufwertung von Nahrungsmitteln durch Zusätze von Vitaminen und eventuell Spurelementen, c) Beeinflussung der Ernährungsgewohnheiten, besonders von Nahrungsauswahl und Zubereitungsart durch Aufklärung und Erziehung.Summary1. In considering various aspects of to-days nutrition those factors are discussed that have contributed to a decreasing intake in protecting food: a) Reduction in caloric requirement. b) Lowering of the avarage concentration in food of vitamins and other essential components. c) Trends in nutritional habits.2. A survey is given on the different ways to improve this situation: a) Regulations dictated by the authorities with respect to price and advertising. b) Enrichement of food by the addition of vitamins and trace elements. c) Improvement of food selection and preparation by means of information and education.

Food and Health: Considerations of the Protein Metabolism with Special Reference to Amino Acid Requirements and Imbalance

Health versus hunger is the most drastic and also the most important contrast in today’s world. It is no exaggeration to state that one of the main conditions for man’s health is the availability of a well balanced nutrition in adequate quantity. There are three reasons to focus these considerations on proteins: They represent — as indicated by the name given to this class by Muldern in 1838 — the body constituent of primary importance. This is true not only quantitatively, but also qualitatively, since all enzymes, the catalysts of living matter, belong to this class. As a food component they have the unique property to be a source of amino acids required for protein synthesis as well as to serve as an energy donor, both aspects being closely related. World wide shortage in supply is most pronounced in this class of foods. The following discussion on the relationship between food and health focuses on the production of more, inexpensive, edible proteins, since this is the most significant area to attack in the battle against hunger.

The isoenzyme pattern: Some comparative-biochemical and developmental aspects

KurzfassungZunächst für einheitlich gehaltene Enzyme sind in zunehmender Zahl aus verschiedenen Isoenzymen bestehend erkannt worden. Diese lassen sich auf Grund ihrer unterschiedlichen elektrophoretischen Beweglichkeit auftrennen. Das Isoenzymmuster eines Organs hängt ab von (1) der Art der beteiligten Gewebe, (2) dem Differenzierungsgrad und (3) der Spezies. Zwei Beispiele werden behandelt: Kreatinkinase (E.C. 2.7.3.2.) und Alkoholdehydrogenase (E.C. 1.1.1.1.). In den Geweben des Säugers kommen 3 Kreatinkinase-Isoenzyme vor. Während im Gehirn ausschließlich der rasch wandernde Typ I vorkommt, enthält Skelettmuskulatur der adulten Ratte ausschließlich den langsam wandernden Typ III. Im Verlauf der Entwicklung erfährt das Isoenzymmuster des Skelettmuskels typische, phasenweise ablaufende Veränderungen. Im frühen Stadium der Embryonalentwicklung ist ausschließlich Typ I zu finden; bei der Geburt kommen alle 3 Typen gleichzeitig vor, wogegen bei alten Ratten nur noch Typ III vorhanden ist. Eine analoge Altersabhängigkeit ist auch beim Hühnerküken zu beobachten; diese Veränderungen laufen hier jedoch wesentlich rascher ab. Die Leberalkoholdehydrogenase besteht je nach Herkunft aus einer verschiedenen Anzahl Isoenzymen. Das Enzym aus der Leber des Menschen läßt sich mittels Agargelelektrophorese in 3 Banden aufteilen; Rhesusaffenleber enthält 2, Pferdeleber 5 Isoenzyme. Beim Rhesusaffen findet sich zudem ein drittes Isoenzym in anderen Organen. Die gereinigten Isoenzyme II und III aus Rhesusaffenleber unterscheiden sich in bezug auf verschiedene kinetische Parameter. Eine atypische Alkoholdehydrogenase wurde beim Menschen gefunden. Sie zeichnet sich gegenüber dem normalen Enzym durch eine hohe spezifische Aktivität sowie durch Unterschiede im pH-Optimum und in der Substratspezifität aus.Summary1.In mammalian tissues three different isoenzymes of creatine kinase can be distinguished. Whereas in brain tissue exclusively type I is found, muscle tissue of the adult rat containes type III only. In ontogeny, however, typical changes in the isoenzyme pattern of skeletal muscle can be observed: In early embryonic stages only type I is found; at birth all three are present. This heterogenous pattern gradually changes to the adult pattern exclusively consisting of isoenzyme III.2.Alcohol dehydrogenase from liver of horse,Macacus rhesus and of man also consists of several isoenzymes. They can be separated by agar gel electrophoresis or chromatography on CM-cellulose. There are three bands in liver tissue of man, only 2 in liver ofMacacus rhesus, whereas 5 different fractions can be distinguished in horse liver.3.In two out of 30 human livers analyzed so far, an atypical enzyme with different kinetic properties has been detected.