This document discusses bisubstrate reactions, where an enzyme catalyzes a reaction involving two substrates that yields two products. Approximately 60% of biochemical reactions are bisubstrate reactions. There are two main types - sequential reactions, where substrates bind and products release in a defined order, and ping pong reactions, where one or more products are released before all substrates are added. Examples of ordered sequential and ping pong bisubstrate reactions are provided.

1. BISUBSTRATE
REACTION
Presented by Fizza Mehwish
Department of Biotechnology
University of Science & Technology, Bannu

2. BISUBSTRATE REACTION
 When an enzyme catalyzing a reaction involving
substrates and yields two products it is called bisubstrate
reaction.
 Approximately 60% reactions accounts for biochemical
reaction.

3.  It is either transferase reaction in which the enzyme catalyzes
the transfer of a specific functional group, from one of the
substrate to the other.
 This reaction is oxidation reduction reaction in which reducing
equivalents are transfer between the two substrate.

4.  W.Cleland introduced nomenclature system for
representing enzymatic reactions;
 Substrate is representing by A,B,C and D.
 Product is represented by P,Q,R and S.
 Stable enzymes forms are designated by E,F and G.
 The number of reactants and products in a given
reaction are specified in order by
UNI(one),Bi(two),Ter(three) and Quad(four).
Nomenclature System

5. BI BI REACTION
 The reaction that requires two substrate and yield two
products that is Bi Bi reaction.
 Types of Bi Bi reaction..

6. Sequential reaction;
All the reactions involved or
bound to the enzyme before
catalysis of the reaction takes
place to release the products.
This also called single
displacement reaction.

7. ORDERED SEQUENTIAL REACTION
 All the substrates are bound to the enzyme in a defined
order or sequence. The products too, are released after
catalysis in a defined order or sequence.

8. EXAMPLE OF ORDERED SEQUENTIAL
REACTION

9. RANDOM SEQUENTIAL REACTION
 The substrate and products are bound and then release
in no preferred order are random order.

10. EXAMPLE OF RANDOM SEQUENTIAL
REACTION

11. PING PONG REACTION
 Mechanism in which one or more products are released
before all substrates have been added are known ass ping
pong reaction.
 It Also called double displacement reaction.

12. EXAMPLE OF PING PONG REACTION