Which of the following is inducible enzyme?
synthesis by induction …a specific enzyme, called an inducible enzyme (e.g., β-galactosidase in Escherichia coli), occurs when cells are exposed to the substance (substrate) upon which the enzyme acts to form a product.
What is a inducible enzyme definition?
[ ĭn-dōō′sə-bəl ] n. An enzyme that is normally present in minute quantities within a cell, but whose concentration increases dramatically when a substrate compound is added.
What is an example of constitutive enzyme?
constitutive enzyme An enzyme that is always produced whether or not a suitable substrate is present. An example is the lac-operon, which controls the synthesis of three enzymes (beta-galactosidase, permease, and acetylase): enzymes that are involved in the lactose metabolism of the bacterium Escherichia coli.
Which enzyme is inducible by insulin?
Induce glycogen synthesis – When glucose levels are high, insulin induces the formation of glycogen by the activation of the hexokinase enzyme, which adds a phosphate group in glucose, thus resulting in a molecule that cannot exit the cell.
Is lactase an inducible enzyme?
Lactase is a non inducible enzyme [1], but it was also reported that continuous lactose consumption decreases hydrogen excretion and the severity of gastrointestinal symptoms [54-58]. Decreased hydrogen excretion is not necessarily the consequence of increased lactose digestion but can depend on adaptative phenomena.
Is amylase an inducible enzyme?
Amylase is an inducible enzyme. The presence of starch as sole carbon source in the production medium is known to trigger amylase production. However, it is also known that amylase production is affected by catabolite repression by starch hydrolytic products such as glucose and maltose [6, 7].
What is a Repressible enzyme?
[ rĭ-prĕs′ə-bəl ] n. An enzyme whose production is generally continuous but can be halted if a particular substance is present in concentrations greater than normal.
Is hexokinase induced by insulin?
Two isoforms of hexokinase, HKI and HKII, are expressed in human skeletal muscle, but only HKII expression is regulated by insulin. HKII messenger RNA, protein, and activity are increased after 4 h of insulin infusion; however, glucose uptake is stimulated much more rapidly, occurring within minutes.
Is Lactose Intolerance a mutation?
Most people in the world are lactose intolerant, but a genetic mutation where a cytosine (C) nucleotide in a person’s DNA is replaced with a thymine (T) nucleotide allows them to digest milk. People who can digest lactose often originate from northwest Europe (like many New Zealanders) and some parts of Africa.
Is lactose persistence a mutation?
Some humans, however, continue to produce lactase throughout adulthood, a trait known as lactase persistence. In European populations, a single mutation (−13910*T) explains the distribution of the phenotype, whereas several mutations are associated with it in Africa and the Middle East.