In 1913, biochemists Michael ic and Menten put forward the theory of intermediate products of enzymes.They believe that the reason why the enzyme reduces the activation energy is that the enzyme participates in the reaction, that is, the enzyme molecule first combines with the substrate molecule to form an unstable intermediate product (intermediate conjugate). This intermediate product is not only easy to generate, but also easy to decompose the product, releasing the original enzyme, thus turning the one step reaction with higher activation energy into a two step reaction with lower activation energy.
In 1913, biochemists Michael ic and Menten proposedmiddleProduct theory.They believe that the reason why the enzyme reduces the activation energy is that the enzyme participates in the reaction, that is, the enzyme molecule first combines with the substrate molecule to form an unstable intermediate product (intermediate conjugate). This intermediate product is not only easy to generate, but also easy to decompose the product, releasing the original enzyme, thus turning the one step reaction with higher activation energy into a two step reaction with lower activation energy.As the activation energy decreases, the activation molecules increase greatly and the reaction speed increases rapidly.If E is the enzyme, S is the substrate, ES is the intermediate product, and P is the end product of the reaction, the reaction process can be expressed as follows: E+S → ES → E+P.
The key of this theory is that the enzyme participates in the reaction of substrate and generates unstable intermediate products, so that the reaction can proceed rapidly along the path of low activation energy.In fact, the theory of intermediate products has been confirmed by many experiments, and intermediate products do exist[1]。
Intermediate product theory is a scientific inference
Announce
edit
The intermediate product theory is a scientific inference, whose expression is concise and easy to teach and learn.Due to the modernization of research means, the intermediate product theory is no longer a hypothesis, but a scientific inference.Its central content can be expressed as E+S←→E.S→P+E said that it would not take time and effort to explain the theory vividly[1]。
Intermediate product theory is the most powerful concept in enzymology
Announce
edit
The intermediate product theory is the most powerful concept in enzymology and should be the center of teaching.Strengthening the teaching of basic concepts is the basic and highest requirement of classroom teaching. In enzymology, the active center of enzyme, zymogen and its activation, isoenzyme, competitive inhibition, non competitive inhibition and other concepts as the focus of teaching are adapted to this teaching law.The intermediate product theory can explain these concepts. According to the "intermediate product theory"→Active center of enzyme→Zymogen and zymogen activation→Competitive inhibitionNon competitive inhibitionThe teaching sequence is to gradually explain the relevant content, and take the intermediate product theory as the assimilation core, so that students can easily form a complete and solid concept of enzyme, so that learning can achieve efficient transfer[1]。
Enzyme substrate transition complex
Announce
edit
The enzyme substrate transition state complex (E.S) proposed by the intermediate product theory can not only be detected by X-ray diffraction method, but also formTransition state theoryIt is being widely used.The students can be convinced of the existence of this transition state compound, and then put forward the concept of active center of enzyme, which can make it concrete, visualized and clear, and provide a strong guarantee for further assimilation of other concepts.
Competitive inhibition, non competitive inhibition
Announce
edit
The teaching of competitive inhibition and non competitive inhibition needs to be explained and inferred by the intermediate product theory.To clarify these two concepts, it is usually necessary to compare the structural relationship between inhibitor (I) and substrate (S), and the effect of changing substrate concentration at the binding site of (I) and enzyme (E) on inhibition. These comparisons and inferences are inseparable from the expression of intermediate product theory.Only in this way can we clarify the meaning of competitive inhibition and non competitive inhibition, and explain the characteristics of the two kinds of inhibition by using the principle of chemical balance[1]。
