Enzymology - Part I

Increasing the substrate concentration does not increase the rate of reaction at a certain point because all of the enzymes are already occupied by substrates. This means that there are no free enzymes available to bind with additional substrates and catalyze the reaction at a faster rate. Once all the enzymes are occupied, the reaction rate reaches a maximum and cannot be further increased by increasing the substrate concentration.

The given answer states that all the pairs regarding enzymes and co-factors are correctly matched. This means that each enzyme listed is indeed associated with the corresponding co-factor mentioned.

Km, or the Michaelis constant, represents the substrate concentration at which the reaction rate is half of Vmax (the maximum velocity). It is a measure of the affinity of the enzyme for its substrate; a lower Km indicates higher affinity, and a higher Km indicates lower affinity.

A) Km = concentration of substrate at ½ Vmax: This is true and is the definition of Km.

B) Km is inversely proportional to the affinity: This is true. A lower Km means higher affinity, and a higher Km means lower affinity.

C) Km is increased in non-competitive inhibition: This is false. In non-competitive inhibition, the Km remains unchanged because the inhibitor affects the enzyme's activity but does not compete with the substrate for the active site.

D) Km is increased in competitive inhibition: This is true. In competitive inhibition, the Km increases because the inhibitor competes with the substrate for the active site, making it appear as though the enzyme has a lower affinity for the substrate.

Serine Protease contain serine at their active site which is a part of catalytic triad.

Hexokinase is an enzyme with low specificity because it can phosphorylate a wide range of hexoses, such as glucose, mannose, and fructose. It does not require a specific substrate and can catalyze the phosphorylation of multiple hexose sugars. In contrast, enzymes with high specificity only work on specific substrates and have a narrow range of substrates they can act upon.

also called dobule reciprocal (1/vo Vs 1/[S]) |
straight line is obtained |
intercept on x-axis is equal to -1/Km & intercept on the y-axis is equal to 1/Vmax.

Enzymes are biological catalysts that speed up chemical reactions in living organisms. They can be either proteins or RNA molecules, depending on the specific enzyme. Some enzymes are made up of proteins, while others are made up of RNA. Therefore, the correct answer is "Both" because enzymes can have a chemical nature of either proteins or RNA.