<prompt> NAD acts as a cofactor forCitrate synthetaseIsocitrate dehyrogenasea ketoglutarate dehyrogenaseMalate dehydrogenase  <response>: In the TCA cycle,Step 3. In the third step, isocitrate is oxidized and releases a molecule of carbon dioxide, leaving behind a five-carbon molecule--a-ketoglutarate. During this step, textNADNAD N, A, D, sta superscript, plus, end superscript is reduced to form textNADHNADHN, A, D, H. The enzyme catalyzing this step, isocitrate dehydrogenase, is impoant in regulating the speed of the citric acid cycle.Ref: DM Vasudevan, 6th edition, page no: 218 