Temperature and red cell metabolism: Effects of α-stat and pH-stat conditions

Guppy, Michael; Sabaratnam, R.; Whisson, M E

doi:10.1016/0306-4565(90)90027-f

Cited by 4 publications

(4 citation statements)

References 22 publications

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“…Our oxygen consumption data at 37°C may be approximately extrapolated to 22°C by assuming a Qlo (ratio of rates with a 10°C change in temperature) of 2, a figure which is typical of many physiological and biochemical processes [17,18]. This gives a rate of 1 pmol/lO'O/h for washed platelets at 22"C, in reasonable agreement with data reported for platelets in glucose/plasma medium at somewhat higher concentrations in plastic storage bags, where reported rates are about 0.6-0.8 pmol/lO1o/h over longer observation times [2,8,9].…”

Section: Discussionmentioning

confidence: 99%

Alternative Fuels for Platelet Storage: A Metabolic Study

Guppy¹,

Whisson

Sabaratnam³

et al. 1990

Vox Sanguinis

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We have studied the metabolism of platelets in vitro using washed platelets. Oxygen uptake and fuel utilization were measured. It was found that glucose is never oxidized to any significant extent and is always converted to lactate, regardless of oxygen availability. Oxidative metabolism fuels 70-100% of the ATP turnover, and oxygen uptake is the same whether the platelet is consuming glucose, acetate or only an unidentified endogenous fuel. When acetate is the added fuel, no endogenous fuel is oxidized, whereas the addition of glucose results in sparing of only 8% of endogenous fuel. Preliminary storage experiments using plasma-free media show that an acetate-containing buffered salt solution provided excellent storage conditions and that a medium without any exogenous fuel is better than one containing glucose. Thus we conclude that a successful storage medium should contain minimal amounts of glucose, and an oxidizable fuel such as acetate, in order to supplement the endogenous one.

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Section: Discussionmentioning

confidence: 99%

Alternative Fuels for Platelet Storage: A Metabolic Study

Guppy¹,

Whisson

Sabaratnam³

et al. 1990

Vox Sanguinis

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“…So, it is not correct to state that a pH of 7.4-7.6 at 4°C is in the physiological range, as suggested for example by Murphy [31], because physiological pH at 4°C is closer to 8.0 than 7.4 [for a discussion of this concept see ref. 9,14,15]. In enzyme reactions, the same principle applies.…”

Section: Introductionmentioning

confidence: 82%

pH, Temperature and Lactate Production in Human Red Blood Cells: Implications for Blood Storage and Glycolytic Control

Guppy¹,

Attwood²,

Hansen³

et al. 1992

Vox Sanguinis

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The interaction of temperature and pH in biological systems comprises two components. Temperature change may perturb the pH of solutions, and it may change the pKa of some ionizable groups that are involved in enzyme catalysis. The pH optima of single reactions and whole pathways are therefore temperature sensitive. The pH optimum of glycolysis in human red cells has been investigated only at 37 °C. We have measured the effect of temperature on the pH of stored blood suspensions and on the pH optimum of glycolysis in the human red cell. The pH of the cell suspensions in a traditional storage medium was 7.25 ± 0.2 at 4°C. The pH optimum of glycolysis was high (7.8-8.5) between 15 and 35 °C. It can be inferred from our data that human red cells are currently stored at least 0.5 pH units below the pH optimum of glycolysis at 4°C. This suggestion is supported by storage experiments which showed that glycolysis at 4°C was at least 1.5-fold more active at an initial pH of 7.67 versus 7.36. Equations which describe the variation in reaction velocity with pH were fitted to the pH curves for glycolysis in order to identify the ionizable groups that contribute to the effect of pH on glycolysis. It is generally accepted that hexokinase catalyses the rate-limiting step in glycolysis in the human red cell, but none of the ionizable groups implicated correspond to that involved in the hexokinase reaction.

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“…because physiological pH at 4°C is closer to 8.0 than 7.4 [for a discussion of this concept see ref. 9,14,15]. In enzyme reactions, the same principle applies.…”

Section: Introductionmentioning

confidence: 95%

pH, Temperature and Lactate Production in Human Red Blood Cells: Implications for Blood Storage and Glycolytic Control

et al. 1992

View full text Add to dashboard Cite

The interaction of temperature and pH in biological systems comprises two components. Temperature change may perturb the pH of solutions, and it may change the pKa of some ionizable groups that are involved in enzyme catalysis. The pH optima of single reactions and whole pathways are therefore temperature sensitive. The pH optimum of glycolysis in human red cells has been investigated only at 37 degrees C. We have measured the effect of temperature on the pH of stored blood suspensions and on the pH optimum of glycolysis in the human red cell. The pH of the cell suspensions in a traditional storage medium was 7.25 +/- 0.2 at 4 degrees C. The pH optimum of glycolysis was high (7.8-8.5) between 15 and 35 degrees C. It can be inferred from our data that human red cells are currently stored at least 0.5 pH units below the pH optimum of glycolysis at 4 degrees C. This suggestion is supported by storage experiments which showed that glycolysis at 4 degrees C was at least 1.5-fold more active at an initial pH of 7.67 versus 7.36. Equations which describe the variation in reaction velocity with pH were fitted to the pH curves for glycolysis in order to identify the ionizable groups that contribute to the effect of pH on glycolysis. It is generally accepted that hexokinase catalyses the rate-limiting step in glycolysis in the human red cell, but none of the ionizable groups implicated correspond to that involved in the hexokinase reaction.

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Temperature and red cell metabolism: Effects of α-stat and pH-stat conditions

Cited by 4 publications

References 22 publications

Alternative Fuels for Platelet Storage: A Metabolic Study

Alternative Fuels for Platelet Storage: A Metabolic Study

pH, Temperature and Lactate Production in Human Red Blood Cells: Implications for Blood Storage and Glycolytic Control

pH, Temperature and Lactate Production in Human Red Blood Cells: Implications for Blood Storage and Glycolytic Control

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