

Link reaction is the step which links the process of glycolysis to Krebs cycle. The reaction can be equated as-
2CH3COCOO- + 2NAD+ + 2H2O
2CH3COO- + 2NADH + 2H+ + 2CO2
The oxidised form of nicotinamide adenine dinucleotide, NAD+, is reduced to its reduced from NADH.
There is no ATP gain in this process.
