acid-phosphatase and Phagocyte-Bactericidal-Dysfunction

Topics: Acid Phosphatase; Agranulocytosis; Blood Bactericidal Activity; Chediak-Higashi Syndrome; Chemotaxis; Child, Preschool; Complement System Proteins; Cytoplasmic Granules; Female; Glucosephosphate Dehydrogenase Deficiency; Humans; Immunologic Deficiency Syndromes; Infant, Newborn; Infant, Premature; Leukocytes; Liver; Lysosomes; Macrophages; Male; Monocytes; Mononuclear Phagocyte System; Muramidase; NADH, NADPH Oxidoreductases; Neutrophils; Opsonin Proteins; Peroxidases; Phagocyte Bactericidal Dysfunction; Phagocytosis; Spleen

We used sensitive isotopic and fluorometric assay procedures to investigate reduced nicotinamide adenine dinucleotide (phosphate) [NAD(P)H]oxidation in a particulate fraction derived from normal and chronic granulomatous disease leukocytes. Granules isolated from normal resting cells showed allosteric kinetics with regard to oxidation of either NADH or NADPH, so that no enzyme activity was observed at physiological concentrations of substrate. If the granules were isolated from cells that had previously phagocytized zymosan, normal hyperbolic kinetics were obtained, so that activity could now be observed at low levels of substrate. The activity towards NADPH was always substantially greater than that towards NADH at any given concentration of substrate. This alteration in kinetics with phagocytosis was not observed with the other granule enzymes, acid phosphatase or beta-glucuronidase, and thus appeared to be specific for the reduced pyridine nucleotide oxidase(s). In contrast, granules isolated from cells of patients with chronic granulomatous disease showed allosteric kinetics regardless of whether they were obtained from resting or phagocytizing cells, so that NADPH oxidation was not measurable at physiological concentrations of substrate. This defect in the oxidation of NADPH by granules isolated from phagocytizing chronic granulomatous disease cells was observed over the pH range of 4.0 to 7.0. These data suggest that initiation of the respiratory burst by pahgocytosis normally requires an allosteric transformation in a reduced pyridine nucleotide oxidase, which in turn allows expression of enzymatic activity at physiological concentrations of substrate. The defect in chronic granulomatous disease appears to lie in an inability to achieve this transformation, and the enzyme remains in the inactive, allosteric form.

Topics: Acid Phosphatase; Allosteric Regulation; Glucuronidase; Humans; Hydrogen-Ion Concentration; Kinetics; NAD; NADH, NADPH Oxidoreductases; NADP; Neutrophils; Phagocyte Bactericidal Dysfunction; Phagocytosis

Topics: Acid Phosphatase; Adult; Antigen-Antibody Complex; Centrifugation; Child; Child, Preschool; Female; Glucuronidase; Humans; Immunoglobulin G; In Vitro Techniques; Kinetics; L-Lactate Dehydrogenase; Lysosomes; Male; Neutrophils; Phagocyte Bactericidal Dysfunction; Phagocytosis; Sex Chromosomes; Time Factors

Topics: Acid Phosphatase; Adult; Alkaline Phosphatase; Azo Compounds; Cell Nucleus; Chediak-Higashi Syndrome; Child; Emulsions; Glucuronidase; Humans; Leukocyte Count; Leukocytes; Lymphocytes; Male; Naphthalenes; Oils; Paraffin; Peroxidases; Phagocyte Bactericidal Dysfunction; Phagocytosis