The ping-pong model for the red cell anion exchange system postulates that the transport protein band 3 can exist in two different conformations, one in which the transport site faces the cytoplasm (Ei) and another in which it faces the outside medium (Eo). This model predicts that an increase in intracellular chloride should increase the fraction of sites in the outward-facing, unloaded form (...

Plant xyloglucan endotransglycosylase (XET, EC 2.4.1.207) degrades its substrate by a transglycosylation mechanism while endo-cleaving xyloglucan (XG) molecules at their beta-1,4-linked polyglucosyl main chain and transferring the newly generated reducing chain ends to hydroxyls at C-4 of non-reducing glucosyl ends of the main chains of other XG molecules or of low-Mr XG-fragments (OS). Kinetic...

Multicopper oxidases (MCOs) catalyzed two half reactions (linked by an intramolecular electron transfer) through a Ping-Pong mechanism: the substrate oxidation followed by the O2 reduction. MCOs have been characterized in details in solution or immobilized on electrode surfaces. The nature of the rate-limiting steps, which is controversial in the literature, is discussed in this mini review for...

This paper presents a novel method for absolute three-dimensional (3D) shape measurement that does not require conventional temporal phase unwrapping. Our proposed method uses a known object (i.e., a ping-pong ball) to provide cues for absolute phase unwrapping. During the measurement, the ping-pong ball is positioned to be close to the nearest point from the scene to the camera. We first segme...

Fusel oil is a by-product of distilleries, its main component is i-amyl alcohol, which can form ester compounds. Esterification of oleic acid and i-amyl alcohol by Candida antarctica lipase B (Novozym 435 preparation) in n-heptane solvent was studied in this work. Ping-pong bi-bi mechanism (inhibition phenomena taken into account) was applied as a complex kinetic model. The parameters of the mo...

1. 2,3-Bisphosphoglycerate phosphatase was partly purified by CM-cellulose column chromatography. 2. The enzyme activity was stable in the 50•Ž case of preincubation up to 30 min. By the addition of 4 mM 2-phosphoglycolate to the preincubation mixture activity remained perfect up to 30 min in the 55•Ž case of preincubation. 3. This enzyme was inhibited by low concentrations of p-chloromercuribe...

Nucleoside diphosphokinase from Salmonella typhimurium has been purified and characterized. In many respects, the enzyme is similar to those from higher organisms in that it has a broad speciCcity for both phosphate donor and recipient and that it functions via a ping-pong mechanism. The enzyme activity of cells is very high at all growth rates but decreases as growth rate increases. Evidence i...

Germline-specific Piwi-interacting RNAs (piRNAs) protect animal genomes against transposons and are essential for fertility. piRNAs targeting active transposons are amplified by the ping-pong cycle, which couples Piwi endonucleolytic slicing of target RNAs to biogenesis of new piRNAs. Here, we describe the identification of a transient Amplifier complex that mediates biogenesis of secondary piR...