Enzymes And Isoenzymes Flashcards
What indicates whether the reaction will proceed without the input of energy but are not indicative of the velocity at which the reaction takes place?
Numerical values of the standard free energy change
What enzyme increases the amount of times carbon dioxide and water coverts to bicarbonate and hydrogen?
Carbonic acid
What are the most important class of biochemical reactions given that biological oxidation provides most of the energy for aerobic metabolism?
Redox reactions
When is energy released through the electron transportt chain?
When electrons are transferred from fuel molecules through the ETC to oxygen
Energy released in the ETC is used for what?
pump hydrogen ions across the mitochondrial membrane
How can kidneys regulate the pH of blood?
They have the ability to remove protons from the blood in the form of ammonium ion and to reabsorb bicarbonate
What does low pH trigger in the kidney?
An increase in both the removal of protons and the reabsorption of bicarbonate
Diabetic ketoacidosis is a condition marked by what?
hyperglycemia and low blood pH that often afflicts individuals with uncontrolled diabetes
The lack of insulin prevents glucose from being taken up by cells to produce energy and consequently, the body switches to degrading _______ for energy.
fatty acid
The degradation via beta-oxidation of fatty acids generates acidic compounds called _______.
ketone bodies
What are examples of ketone bodies?
acetone, acetoacetic acid, beta-hydroxybutyric acid
The dissociation of ketone bodies releases what?
H, which causes the pH of blood decrease
What are the symptoms diabetic ketoacidosis?
dehydration, vomiting, confusion, and coma and may lead to death
Describe the gastric proton pump
H/K ATPase pump located in parietal cells that line the gastric lumen, pumps protons into gastric lumen, where they combine the Cl to create HCl, a key component of gastic acid
What are drugs that inhibit the gastric proton pump?
omeprazole, iansoprazole, esomeprazole.
What does the reduction of HCl production cause?
Hypocholorhydria, which leads to a decrease in the absorption of nutrients, an increase in sensitivity to food poisoning, and a reduction in the efficacy of gastric enzymes
What is a pharmaceutical agent used for the treatment of chronic gout- a condition caused by the accumulation of uric acid in the synovial fluids surrounding joints and marked by throbbing pain due to the inflammation of joints?
allopurinol
What is the target of allopurinol?
Xanthine oxidase; converts hypoxanthine to xanthine and then uric acid in purine degradation
Why is allopurinol often described as suicide inhibitor/inactivator?
bc its mechanism of action involves binding to the active site of xanthine oxidase, which then converts allopurinol into its active metabolite, alloxanthine. The latter binds tightly to the active site and is only slowly released from it.
At low concentrations, allopurinol is described as a ________ inhibitor, but at high concentration, it is described as ______ inhibitor?
competitive, noncompetitive
What is an autoimmune disease caused by an inhibition of acetylcholine signaling by antibodies that bind to and thus block acetylcholine nicotinic receptors from binding to their cognate ligand, acetylcholine?
myasthenia gravis
Patient shows signs of muscle weakness, inability to hold one’s gaze, and fatigue. What is the disease and recommended treatment?
Myasthenia gravis
Acetylcholinesterase inhibitors such as physostigmine, neostigmine, and pyridostigmine (reversible inhibitor)
What inhibits metalloenzymes?
chelating agents that bind to and remove the metal cofactors from the metalloenzyme. Ethylenediaminetetraacetic acid
Patient; 8 shows symptoms: abdominal pain, sideroblastic anemia, irritability, headaches, and signs of impaired nervous development and encephalopathy. Patient lives in older building dating back to 1960. Diagnosis
Possible lead poisoning. Lead inhibits ALA dehydratase and ferroochelatase, enzymes involved in the biosynthesis ofheme. Treatment with EDTA because lead has an higher affinity for EDTA than does calcium and is excreated in the urine. Children can be treated with chelating agent succimer
What is troponin?
a protein complex that plays a role in muscle contraction and relaxation triggered by elevated or depressed levels of intracellular Ca respectively