Enzymes???

WHAT ARE ENZYMES YOU ASK???
An enzyme is a specialized protein that catalyzes a chemical reaction of a cell.


Catalyzes?
to bring about the catalysis of a chemical reaction.

Catalysis??
a modification and especially increase in the rate of a chemical reaction induced by material unchanged chemically at the end of the reaction.

HOW DOES CATALYSIS OCCUR???

WHAT IS A SUBSTRATE???

A substrate is a molecule upon which an enzyme acts. Enzymes catalyze chemical reactions involving the substrate(s).

HOW DO ENZYMES WORK???

Enzymes provide a way for responses to occur at the cell's normal temperature. An enzyme doesn't supply starting energy to the responding molecules, but instead lowers the energy requirement hurdle so that the reaction can proceed at normal cell temperatures.

The sparks generated by striking steel against a flint provide the activation energy to initiate combustion in this Bunsen burner. The blue flame will sustain itself after the sparks are extinguished because the continued combustion of the flame is now energetically favorable.

HOW DO ENVIRONMENTAL FACTORS AFFECT ENZYMES???

Temperature and pH are the two greatest factors that can affect how well, if at all, an enzyme is able to function. The shape and structure of an enzyme is vital to its operation. Changes to the surrounding environment of an enzyme can greatly affect its survival and purpose.

THE ROLE OF THE ENZYMES: Amylase, Lipase, Sucrase, and Pepsin IN THE BODY.

Amylase - is an enzyme present in human saliva where it begins the digestion process. It helps to breakdown starches into sugar. Below is a diagram of an amylase molecule from human saliva.

The pancreas also makes amylase. Below is a diagram of a pancreatic amylase enzyme.

Lipase - a water-soluble enzyme that catalyzes the chemical reaction of ester bonds in water-insoluble, lipid substrates. Lipases perform vital functions in the digestion, transport, and processing of dietary lipids (e.g. triglycerides, fats, oils) in most living organisms. Below is a diagram of a pancreatic lipase enzyme.

Sucrase - the name given to a number of enzymes that catalyse the chemical reaction of sucrose to fructose and glucose. The diagram below shows the hydrolysis of sucrose to glucose and fructose by sucrase.

Pepsin - is a digestive protease* released by the chief cells in the stomach that functions to degrade food proteins into peptides (small digestibles).

*any enzyme that conducts proteolysis**

**the directed digestion of proteins by cellular enzymes called proteases

Diagram of pepsin in complex with pepstatin.