Enzymes that require NAD are isocitrate dehydrogenase, glyceraldehyde-3-phosphate dehydrogenase and malate dehydrogenase. Hence the correct options are b, c and d.
Enzymes play critical roles in cellular processes, and several of them are involved in metabolic pathways that require the coenzyme nicotinamide adenine dinucleotide (NAD). Isocitrate dehydrogenase, a key enzyme in the citric acid cycle, utilizes NAD as a coenzyme during the conversion of isocitrate to alpha-ketoglutarate. Similarly, glyceraldehyde-3-phosphate dehydrogenase, a pivotal enzyme in glycolysis, utilizes NAD in the conversion of glyceraldehyde-3-phosphate to 1,3-bisphosphoglycerate.
Malate dehydrogenase, involved in the citric acid cycle, uses NAD during the conversion of malate to oxaloacetate. In each case, NAD serves as a crucial electron carrier, facilitating redox reactions and energy transfer within the cell. These enzymatic processes contribute to the overall regulation and efficiency of cellular metabolism. Hence the correct options are b, c and d.