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Boyer and Walker shared half of the 1997 Nobel Prize in chemistry for
the discovery of the mechanism of formation of ATP from ADP at ATP
synthase. Within plant cells, most energy is transferred through a carrier
ATP, known as the universal currency for energy transfer. The terminal
phosphate radical is attached by an energy-rich bond. When this bond is
hydrolysed, the terminal phosphate radical is released from ATP and large
amounts of energy are produced. Conversely, the same amount of energy
is required to form ATP.

Figure 13. Energy transfer via ATP in plant cell

Enzyme Specificity

Enzymes are said to be specific. This means that any given enzyme

catalyses chemical change for only one type of substrate, since it is specific

for a particular atomic group or Linkage (Figure 14) e.g.

Sucrase

Sucrose (Fruc-Glu)  Fructose + Glucose

Raffinose Sucrase
(Fruc--Glu – Gal)  Fructose + Melibiose

Raffinose Melibiase
(Fruc-Glu – Gal)  Sucrose + Galactose

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