The Influence of Temperature on Malic Acid Metabolism in Grape Berries

Abstract

Phosphoenolpyruvate (PEP) carboxylase activity in immature 'Carignane' grape berries (Vitis vinifera L.) had a temperature optimum of about 38 C, whereas malic enzyme activity rose with increasing temperature between 10 and 46 C. In vitro temperature inactivation rates for the PEP carboxylase were markedly greater than for the malic enzyme activity. From the simultaneous action of malic acidproducing enzymes (PEP carboxylase and malic dehydrogenase) and malic acid-degradating enzyme (malic enzyme) systems at different temperatures, the greatest tendency for malic acid accumulation in immature grape berries was at 20 to 25 C. Time-course measurements of enzymic activity from heated, intact berries revealed greater in vivo temperature stability for the malic enzyme activity than for the PEP carboxylase activity.

Phosphoenolpyruvate Carboxykinase Activity in Grape Berries

“…Previous experiments in this laboratory (19) showed that malate dehydrogenase activity in grape berry extracts always exceeded that of PEP carboxylase, by a factor of at least ten. Thus, the "C-OAA formed by PEP carboxylase is immediately reduced to malic acid.…”

“…Buffers: potassium phosphate, pH 6; to sugars occurred at 20 C (26). Lakso (19) found that malic 1, pH 6.2 to 7. Plant Physiol.…”

“…For comparative purposes, PEP carboxylase activity was also measured, as the activity of this enzyme in grapes has been measured by several investigators (14,19,23). In addition, some of the properties of PEP carboxykinase in grape berries were investigated, since, so far as we are aware, this enzyme has not been characterized in fruits of woody plants.…”

Fruit zone leaf removal influences vegetative, yield, disease, fruit composition, and wine sensory attributes of Vitis vinifera L. 'Optima' and 'Cabernet franc'

“…Enhanced fruit exposure usually advances berry maturity as a result of elevated berry temperature and enzyme activity to reduce malic acid (Lakso and Kliewer 1978;Reynolds and Wardle 1989). However, malic enzyme activity requires a berry temperature of at least 30°C (Lakso and Kliewer 1978) which was present for Optima but not for the later maturing Cabernet franc.…”

Research on the quality of the wine grapes in corridor area of China

“…Several studies have demonstrated a positive association between temperature and seed number or total proanthocyanidin concentrations per berry at harvest (Del Rio & Kennedy, 2006;Ewart & Kliewer, 1977). The influence of temperature on total acidity has been widely discussed (Koundouras et al, 2006) and higher concentrations have been reported in grapes grown in cool regions than that of grapes from warm regions (Lakso & Kliewer, 1975). In the present study, the temperature of Zhangye was moderate when compared with that of Wuwei and Jiayuguan, and the low temperatures and GDD of Jiayuguan might have resulted in the low concentrations of phenols (Table 3).…”