Question

1. using your knowledge of nutritional physiology and creative thought processes, explain the ramifications to human metabolism and health if the kidneys were lacking the glutaminase enzyme.

Answer 1

Answer-

According to the given question-

• We know that Glutamine is one of the most abundant amino acid which are present in human body and responsible for several metabolic process.
• It work as glucose precursor and also work as substrate for renal gluconeogenesis.
• renal gluconeogenesis responsible for approximately 20-25% of glucose produced by whole body, also responsible for stimulation of muscle glycogen storage as well as gluconeogenesis.
• In type II diabetes human there is increase amount of conversion of glutamine into glucose occur.
• Glutamine is synthesized form glutamate and α-ketoglutarate with the help of enzyme glutamine synthetase and glutamate aminotransferase respectively in cytosol.
• glutamine is degraded into glutamate with the help of enzyme glutaminase found in the matrix of mitochondria. glutamate is transaminated with the help of enzyme present in cytosol called glutamate oxaloacetate-transaminase or with the enzyme present in mitochondrial matrix called glutamate-alanine-transaminase, and glutamate is deaminated with the enzyme of mitochondrial matrix called glutamate dehydrogenase and produces α-ketoglutarate, which is a intermediate product of tricarboxylic acid cycle.
• glutamine is converted into glucose in liver hepatocytes as well as in kidney or renal tubular cells by several process such as via transamination to α-ketoglutarate , through deamination into glutamate,as well as directly converted into oxaloacetate which is also a intermediate of Krebs cycle.
• Gluconeogenesis is the process of glucose synthesis from nonglucose precursors such as from amino acid such as glutamine and responsible for approximately 50% glucose released during overnight fasting in human.
• Gluconeogenesis occur only in liver and kidney due to presence of glucose-6-phosphatase enzyme but gluconeogenic capacity of kidney is more than liver.
• Lack of glutaminase enzyme play a big factor in the process of gluconeogenesis because due to lack of glutaminase enzyme glutamine was unable to degrade into glutamate.
• Glutaminase found in epithelial cells of renal tubules responsible for producing glutamate and ammonia which is later excreted as ammonium ions.