The Production of Pyruvate and Acetaldehyde During the Fermentation of Glucose.
ABSTRACT
The glycolysis pathway is nearly universal in biological systems. Glycolysis is the sequence of reactions that converts glucose to pyruvate with the concomitant formation of ATP. Three fates of this pyruvate produced exist. In this practical the production of pyruvate and acetaldehyde by fermentation of glucose is established. A series of test tubes was set up each containing glucose and yeast suspension in buffers at different pH values. These test tubes were incubated for an hour at 37℃. Trichloro-acetic acid solution was then added to the first 2 of the 4 test tubes prior to centrifugation at 2500g. Solid ammonium sulphate and freshly prepared sodium nitroprusside were added to these tubes and colour observations made. For the remaining 2 tubes sodium nitroprusside and aqueous pyrrolidine were added to the supernatant and colour changes observed.
INTRODUCTION/LIERATURE REVIEW
Three alternative catabolic routes are taken by the pyruvate formed by glycolysis. In aerobic organisms or tissues, under aerobic conditions, glycolysis constitutes only the first stage in the complete degradation of glucose. Pyruvate is oxidized, with loss of its carboxyl group as CO2, to yield the acetyl group of acetylcoenzyme A, which is then oxidized completely to CO2 by the citric acid cycle. The electrons from these oxidations are passed to O2 through a chain of carriers in the mitochondrion, forming H2O. (Voet and Voet; 2011). The energy from the electron transfer reactions drives the synthesis of ATP in the mitochondrion. The second route for pyruvate metabolism is its reduction to lactate via lactic acid fermentation. When a tissue such as vigorously contracting skeletal muscle must function anaerobically, the pyruvate cannot be oxidized further for lack of oxygen. Under these conditions pyruvate is reduced to lactate. Certain tissues and cell types (retina, brain, and erythrocytes) convert glucose to lactate even under aerobic conditions. Lactate (the dissociated form of
The glycolysis pathway is nearly universal in biological systems. Glycolysis is the sequence of reactions that converts glucose to pyruvate with the concomitant formation of ATP. Three fates of this pyruvate produced exist. In this practical the production of pyruvate and acetaldehyde by fermentation of glucose is established. A series of test tubes was set up each containing glucose and yeast suspension in buffers at different pH values. These test tubes were incubated for an hour at 37℃. Trichloro-acetic acid solution was then added to the first 2 of the 4 test tubes prior to centrifugation at 2500g. Solid ammonium sulphate and freshly prepared sodium nitroprusside were added to these tubes and colour observations made. For the remaining 2 tubes sodium nitroprusside and aqueous pyrrolidine were added to the supernatant and colour changes observed.
INTRODUCTION/LIERATURE REVIEW
Three alternative catabolic routes are taken by the pyruvate formed by glycolysis. In aerobic organisms or tissues, under aerobic conditions, glycolysis constitutes only the first stage in the complete degradation of glucose. Pyruvate is oxidized, with loss of its carboxyl group as CO2, to yield the acetyl group of acetylcoenzyme A, which is then oxidized completely to CO2 by the citric acid cycle. The electrons from these oxidations are passed to O2 through a chain of carriers in the mitochondrion, forming H2O. (Voet and Voet; 2011). The energy from the electron transfer reactions drives the synthesis of ATP in the mitochondrion. The second route for pyruvate metabolism is its reduction to lactate via lactic acid fermentation. When a tissue such as vigorously contracting skeletal muscle must function anaerobically, the pyruvate cannot be oxidized further for lack of oxygen. Under these conditions pyruvate is reduced to lactate. Certain tissues and cell types (retina, brain, and erythrocytes) convert glucose to lactate even under aerobic conditions. Lactate (the dissociated form of
References: * Hames .B.D., Hooper N.M; (2005); Instant notes in Biochemistry; 2nd Edition; Taylor e-Library; Leeds. * Koolman .J. Roehm .K.H.; (2005); Color Atlas of Biochemistry; 2nd Edition; Thieme Stuttgart; New York. * Sadasivam .S. and Manickam .A.; (2005); New Age: Biochemical Methods; 2nd edition; New Age International (P) Ltd. Publisher; Daryaganj; New Delhi. * Voet .D. and Voet .J.G.; (2011); Biochemistry; 4th edition; John Wiley & Sons Inc.; New Jersey. * Wrolstad .R.E. Decker .E.A., Schwartz .S.J. and Sporns .D; (2005); Handbook of Food Analytical Chemistry; John Wiley & Sons Inc.; New Jersey.