Question

Both enzyme A and enzyme T act on cellobiose. They have a similar, but not identical, primary structure. Suggest how similarities and differences in the primary structure of the two enzymes could help to explain the results obtained in the investigation.

a) Similarities in primary structure may indicate a common substrate.
b) Differences in primary structure may affect enzyme specificity.
c) Similarities in primary structure suggest the enzymes are not related.
d) Differences in primary structure have no impact on enzyme function.

Answer 1

Similarities in primary structure suggest a common substrate for enzyme A and T, while differences may affect enzyme specificity and active site shape.

Step-by-step explanation:

The similarities and differences in the primary structure of enzyme A and enzyme T, which both act on cellobiose, can explain the results obtained in a biochemical investigation. Similarities in the primary sequence suggest that both enzymes have evolved to recognize the same molecular structure, which in this case is cellobiose. However, slight differences in the primary structure can significantly impact the shape of the enzyme's active site and, as a result, its substrate specificity. While both enzymes bind and act on the same substrate, they might interact differently with the substrate, resulting in different rates of reactions or variations in the reaction products due to their specific active sites.

Enzymes are known for their specificity because of the precise way the substrate fits into the active site, often described as a 'lock-and-key' model or through the concept of induced fit. Therefore, changes in primary structure can influence enzyme activity by altering the structure of the active site or by affecting the enzyme's stability and its overall conformation.

In summary, both similarities in primary structure indicating a common substrate and differences affecting enzyme specificity are important considerations for enzyme function and their interaction with substrates.