If PEP carboxykinase were to operate in a direction opposite to its \"normal\" m
ID: 66919 • Letter: I
Question
If PEP carboxykinase were to operate in a direction opposite to its "normal" mode (i.e., not in the gluconeogenic direction), then which of the following would be its substrates and which would be the products? Question 16 options:
Oxaloacetate and GDP would be the substrates and PEP, carbon dioxide, and GTP would be the products.
Oxaloacetate and GTP would be the substrates and PEP, carbon dioxide, and GDP would be the products.
PEP, carbon dioxide, and GTP would be the substrates, and oxaloacetate and GDP would be the products.
PEP, carbon dioxide, and GDP would be the substrates, and oxaloacetate and GTP would be the products.
PEP and GTP would be the substrates, and oxaloacetate, carbon dioxide, and GDP would be the products.
PEP and GDP would be the substrates, and oxaloacetate, carbon dioxide, and GTP would be the products.
Explanation / Answer
Ans. PEP, carbon dioxide, and GDP would be the substrates, and oxaloacetate and GTP would be the products.
During its normal mechanism of catalysis, PEP carboxykinase uses oxaloacetate and GTP as its substrates, the products being GDP and PEP, with liberation a CO2. If the reverse is to occur, the substrates of gluconeogensis becomes products, and the products of gluconeogenesis becomes substrates.