BIOKIMIA PDK ENZIM

Summary

This lecture delves into the role of enzymes in biological processes, explaining their function as catalysts that accelerate reactions without being consumed. The lecture covers enzyme properties, such as their specificity for substrates, and the mechanisms behind enzyme activity (lock-and-key and induced fit models). It also highlights the significance of enzymes in digestion, diagnostics, and industrial applications. Factors influencing enzyme activity, including temperature, pH, and concentration, are discussed, along with enzyme inhibition types. The lecture emphasizes the importance of enzymes in metabolism, health diagnostics, and various industrial sectors.

Takeaways

• 😀 Enzymes are biological catalysts that speed up chemical reactions without being consumed in the process.
• 😀 Enzymes are highly specific to the substrates they act on, meaning each enzyme works on a particular type of substrate (e.g., amylase for starch).
• 😀 Enzymes are proteins that fold into three-dimensional shapes, forming an active site where the substrate binds.
• 😀 The enzyme-substrate complex forms when an enzyme binds to its substrate, facilitating the chemical reaction and producing a product.
• 😀 The 'Lock and Key' model explains enzyme specificity, where the enzyme's active site fits the substrate like a key fits a lock.
• 😀 The 'Induced Fit' model describes how the enzyme's active site changes shape to better accommodate the substrate upon binding.
• 😀 Factors that influence enzyme activity include enzyme and substrate concentration, temperature, pH, and salinity.
• 😀 Enzyme activity increases with higher concentrations of either enzyme or substrate, but it reaches a saturation point where no further increase in rate occurs.
• 😀 Extreme temperatures can denature enzymes, while low temperatures slow down enzyme activity, reducing the rate of reactions.
• 😀 Enzymes have optimal pH ranges depending on their function (e.g., pepsin in the stomach works best in acidic conditions).
• 😀 Enzyme inhibitors can be competitive (competing with the substrate for the active site) or non-competitive (binding elsewhere on the enzyme to alter its shape).

Q & A

What is the primary function of enzymes in the body?

Enzymes act as biological catalysts, speeding up metabolic reactions without being consumed or altered in the process. They help break down substances like carbohydrates, proteins, and fats into smaller, absorbable molecules.

What is the difference between the Lock and Key model and the Induced Fit model?

The Lock and Key model suggests that enzymes and substrates fit perfectly together, like a key fitting into a lock. The Induced Fit model, however, proposes that the enzyme's active site changes shape slightly when the substrate binds, ensuring a better fit.

How do enzymes speed up reactions without being consumed?

Enzymes facilitate reactions by lowering the activation energy required for the reaction to occur. They bind to substrates, form an enzyme-substrate complex, and help convert the substrate into a product without changing themselves.

What are some examples of factors that affect enzyme activity?

Factors that affect enzyme activity include temperature, pH, enzyme concentration, substrate concentration, and the presence of activators or inhibitors.

What is the role of amylase in digestion?

Amylase is an enzyme found in saliva that breaks down starch (a carbohydrate) into smaller sugar molecules like maltose, making it easier for the body to absorb glucose during digestion.

What is competitive enzyme inhibition?

Competitive inhibition occurs when an inhibitor molecule competes with the substrate for the enzyme's active site. This prevents the substrate from binding and slows down the reaction.

How does temperature affect enzyme activity?

Temperature affects enzyme activity by influencing the enzyme's shape and speed of reaction. While each enzyme has an optimal temperature, extreme temperatures can cause denaturation, where the enzyme loses its functional shape.

Why do enzymes have specificity for certain substrates?

Enzymes have specificity due to their unique active site structure, which is tailored to bind with specific substrates. This ensures that enzymes catalyze only particular reactions in the body.

How do cofactors and coenzymes influence enzyme activity?

Cofactors are inorganic molecules (e.g., metal ions like magnesium or iron) that help activate enzymes. Coenzymes are organic molecules that bind to enzymes and assist in the enzymatic reaction, both essential for many enzymes' functions.

What is the significance of SGOT and SGPT enzyme levels in medical diagnoses?

SGOT (AST) and SGPT (ALT) are enzymes that can indicate liver function. Elevated levels of these enzymes in blood tests can signal liver damage or diseases such as hepatitis or cirrhosis.