Experiments on the function of pantothenate in bacterial metabolism

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Abstract
In washed suspensions of Proteus morganii grown with suboptimal supplies of pantothenate, the addition of pantothenate increased the aerobic metabolism of pyruvate to a greater extent than that of 15 other substrates and the anaerobic metabolism of pyruvate more than that of 9 other substrates tested. The opt. pH for the effect of pantothenate was 7 for aerobic and 8 for anaerobic metabolism, but the opt. pH for total O2-uptake was 6. The substrates which gave increases in O2-uptake approaching that with pyruvate were 6 C4 and C5 dicarboxylic acids, and lactate. Little or no fermentation of these substrates, or of malate or glycerol, was detected manometrically, but all (except lactate which was not tested) increased the rate of fermentation of pyruvate. With the C4 dicarboxylic acids, including malate but not succinate, the increase was several-fold. With glutamate, [alpha]-ketoglutarate, aspartate or oxalacetate (and possibly succinate) as substrate, the increase in the O2-uptake promoted by pantothenate tended to occur at the expense of that similarly promoted with pyruvate as substrate. With glucose as substrate fermentation was practically unaffected by pantothenate, and O2-uptake was increased only in the later stages.