Question

Which of the following is not correct for enzyme catalysis?
(a) The enzyme activity is maximum at optimum pH which is between 5-7.
(b) Each enzyme is specific for a given reaction.
(c) The favourable temperature range of enzyme activity is 50-60$^{ o }{ C }$.
(d) The enzymatic activity is increased in presence of certain substances called coenzymes.

Answer 1

Hint: Enzymes are globular proteins that act as biocatalysts. Some enzymes require a non-protein component for their activation and enzymatic activity. They are highly specific and require an optimum pH and temperature for normal functioning.

Complete step-by-step answer:
Let us first understand enzymes. Enzymes are globular proteins that act as biocatalysts. They increase the rate of a reaction by providing alternate lower activation energy pathways. They are commonly named by adding the suffix ‘ase’ to the name of their substrate. For example the enzyme maltase is named so because it catalyses the hydrolysis of maltose to glucose. The reaction is given below:

$\begin{matrix} { C }_{ 12 }{ H }_{ 22 }{ O }_{ 11 } \\ Maltose \end{matrix}+\begin{matrix} { H }_{ 2 }O \\ Water \end{matrix}\xrightarrow { Maltase } \begin{matrix} 2{ C }_{ 6 }{ H }_{ 12 }{ O }_{ 6 } \\ Glucose \end{matrix}$
But according to the IUPAC nomenclature, enzymes should be named in accordance with the type of reaction that they catalyse. For example hydrolases catalyse the hydrolytic reactions.
There are certain enzymes that require a non-protein component for their activation and enzymatic activity. These non-protein components are called cofactors and they are of two types:

-Inorganic ions: example ${ Mg }^{ 2+ },{ Fe }^{ 2+ },{ Na }^{ + },{ K }^{ + }$ etc.

-Organic molecules: These organic molecules could be (i) Coenzymes and (ii) Prosthetic groups.
(i) Coenzymes: Organic molecules that are weakly held by the protein enzyme and can be easily separated. Vitamins such as thiamine, niacin etc. are the general precursors for these organic molecules.
(ii) Prosthetic groups: These organic molecules are strongly bound to the enzyme through covalent bonds. Vitamins such as biotin etc. are the general precursors for these organic molecules.
Enzymes are highly specific in nature, therefore each bio-reaction is associated with a different type of enzyme. There are about 3000 different types of enzymes present in a typical cell.

Enzymes are affected by the pH as well as the temperature drastically since they require an optimum pH and temperature for their normal functioning. Their optimum pH lies around 5-7 while their optimum temperature range is $25-30^{ o }{ C }$.
Keeping all of the above points is mind we can now arrive at the correct answer.
Hence the incorrect statement is (c) The favourable temperature range of enzyme activity is 50-60$^{ o }{ C }$.

Note:
In globular proteins the polypeptide chain is folded in such a manner that the hydrophobic part is present inwards in the spherical/globular structure while the hydrophilic part is pointing outwards. For enzymes, the protein-cofactor complex is referred to as holoenzyme while the protein (which is inactive in absence of the cofactor) is called apoenzyme.