Warburg apparatus

Chromatographic Separations and Implications. Fractionation of hydrilla-inhibiting extracts has perhaps produced the most interesting results concerning the basis for hydrilla inhibition. Two fractions were generated, and best results were obtained with an older, preparative-scale Zorbax column. The effect of both fractions on hydrilla was tested using Warburg apparatus the first fraction did not affect either plant respiration or photosynthesis. The... 

Carbon dioxide is not a common oxidation product in periodate work, but it does appear in the oxidation of ketoses,49 a-keto acids,14,39 and a-hydroxy acids,14 39 and it is often a product23 141 of overoxidation. Carbon dioxide analyses have been carried out using the Plantefol apparatus,49 the Warburg apparatus,14 23 and the Van Slyke-Neill mano-metric apparatus,39 and by absorption in standard sodium hydroxide141 followed by back-titration with acid. A most convenient method is the very old, barium hydroxide absorption scheme.16 The carbon dioxide is swept from the reaction mixture into a saturated, filtered barium hydroxide solution by means of a stream of pure nitrogen. The precipitated barium carbonate is filtered, dried, and weighed. This method is essentially a terminal assay. The manometric methods permit kinetic measurements, but involve use of much more complicated apparatus. 

Detection of heterozygote 02 consumption Distinguishes galactosemics, heterozygotes and normals with minimum overlap Warburg apparatus (K10)... 

Detection of heterozygote 02 consumption Modification of 6. similar results Warburg apparatus (H12)... 

Determination of enzyme 02 consumption Measures true enzyme activity good discrimination heterozygotes, normals and galactosemics Warburg apparatus (S12)... 

The manometric method using the Warburg apparatus is highly accurate, but complicated, and demands more time than the simple spectrophotometrical assay, its accuracy being equal. 

The polyphenol oxidase was obtained from extracts of the pressed grape juice sediment by acetone precipitation, purified on Sephadex G 25 and DEAE-Sephadex A 25, and further concentrated by ultrafiltration. Model experiments were done in a Warburg apparatus (10). The grape skin waxes were extracted with pentane. The resulting extracts were analyzed by a GLC (Varian Aerograph, model 1201) which was coupled via a helium separator according to Watson and Bieman (19) to a mass-... 

Miscellaneous. A manometric technique utilizing a Warburg apparatus has been used to follow esterase activity. The carbon dioxide liberated from sodium bicarbonate by the fatty acids is measured (Willart and Sjostrom 1959). An agar diffusion procedure has been utilized for screening microorganisms for lipolyptic enzymes. The presence of lipase is indicated by clear zones in the turbid media (Lawrence et aL 1967). 

Barakat et al. observed that on treatment with NBS in aqueous solution an a-amino acid (alanine) and a dicarboxylic acid (oxalic) undergo decarboxylation with liberation of bromine. Luck showed that a-amino acids, peptides, and proteins on treatment with NBS (2 equiv.) in aqueous solution undergo quantitative decarboxylation. The reaction is complete in 30 min. with quantitative evolution of COj, as determined in a Warburg apparatus. The first stable product formed is the aldehyde. 

GOase activity is conventionally assayed in a Warburg apparatus to measure the uptake of oxygen (Guilbault, 1976). Electrochemical methods (potentiometric or amperometric) are less sensitive than the fluorimetric methods, but are well-suited for automation (Pardue et al., 1964 Blaedel and Olson, 1964). 

The catalase-like properties of hemocyanin and copper-amino acid chelates have been measured manometrically using a conventional Warburg apparatus. We are now using a differential manometer technique for measuring the rates of oxygen evolution (31) which, for our purposes, is much superior to the conventional vertical column differential manometer, especially in sensitivity. 

In this section a method developed by Schultz, Atkin and Frey may also be mentioned, based on the stimulation by thiamine of the fermentation of glucose by baker s yeast (S. cerevisiae) in the presence of ammonium sulfate. Carried out in a Warburg apparatus, it can measure 0.01-0.02 fig of thi-amine32. jiiis method has been widely used. The effect of thiamine on fermentation has been shown to depend quantitatively upon the formation of carboxylase the coenzyme being derived from thiamine, and ammonium sulfate in the medium providing material for the synthesis of enzyme protein . Under the circumstances of the test carboxylase is evidently a Umiting enzyme for fermentation. 

Warburg and Uyesugi 10.5 — 0.0067 20 During 15 min. Barcroft-Warburg apparatus... 

In 1946 Randall (279) found that Mn02 is reduced by the SH groups of the proteins and is often rendered inactive thereby. He therefore advocates the addition of catalase to terminate the peroxidase action and to decompose the residual substrate. Altschul and Karon (26) also stopped the peroxidase action on pyrogallol after 5 minutes with catalase and determined the O2 developed in a Warburg apparatus. Sizer and co-workers recently (319,361) used a similar peroxidase assay. 

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