Enzymes Lecture Notes Overview

Enzymes are biological catalysts that speed up chemical reactions in living organisms.

Enzymes have specific properties that affect their function, such as location within the cell, and impact on speeding up the reactions.

Enzymes lower the activation energy needed for chemical reactions to occur, making them happen faster.

Enzymes have a specific structure and are named according to the reactions they catalyze.

Enzymes are categorized by the type of reaction they catalyze.

Several factors, like temperature and pH, can influence enzyme function.

Study of enzymes in the blood to diagnose diseases.

Enzymes are crucial for coordinating all biochemical and metabolic reactions in the body.

A substance that speeds up a chemical reaction without being consumed.

A biological catalyst, usually a protein, that speeds up chemical reactions in living organisms.

The part of an enzyme where the substrate binds and the reaction occurs.

An enzyme composed only of amino acids.

An enzyme made of a protein (apoenzyme) and a non-protein helper (cofactor).

The non-protein part of a conjugated enzyme, which helps it function.

The energy needed to start a chemical reaction.

The substance that an enzyme acts upon.

Enzymes greatly accelerate reactions, making them occur 10^3 to 10^8 times faster than uncatalyzed reactions.

The rate at which an enzyme catalyzes a reaction.

The minimum amount of energy needed to start a chemical reaction. Enzymes lower the activation energy.

A unique four-digit code that classifies enzymes based on their function.

Indicates the enzyme class (e.g., oxidoreductase, transferase).

Represents the chemical group acted upon by the enzyme (e.g., -OH, -CHO).

Identifies the cofactor required by the enzyme (e.g., NAD+).

Specifies the specific substrate of the enzyme.

The amount of specific enzymes found in the blood, often indicating tissue damage.

Changes in specific enzyme levels in the blood can help doctors identify and monitor diseases affecting various organs.

Elevated levels of specific intracellular enzymes in the blood often signal tissue damage or disease.

Different molecular forms of an enzyme with the same catalytic function but varying structures.

Allow for more precise diagnosis by indicating the specific tissue origin of the enzyme.

Specific enzymes that can be used to detect and monitor certain diseases.

Heart attack

Conditions affecting the liver

The speed of an enzyme-catalyzed reaction increases as the amount of substrate increases, until it reaches a maximum velocity called Vmax. This happens when all enzyme active sites are occupied by substrate molecules.

The relationship between enzyme velocity and substrate concentration is typically represented by a hyperbolic curve. This means the velocity increases rapidly at first, then slows down and plateaus.

Allosteric enzymes show a sigmoidal curve, indicating a different pattern of reaction velocity versus substrate concentration. Their activity is influenced by binding of molecules at sites other than the active site.

Higher enzyme concentration leads to higher reaction velocity, up to a point. Increasing enzyme concentration increases the number of active sites available for substrate binding, accelerating the reaction.

Every enzyme has a specific temperature at which it functions best. Above or below this temperature, the enzyme's activity slows down or may even stop due to denaturation.

High temperature can cause an enzyme to lose its shape and ability to function, making it inactive. This is like altering the key so it no longer fits the lock.

Each enzyme works best at a specific pH. Outside this range, the enzyme's activity decreases due to changes in its ionic state. Extreme pH can denature the enzyme.

Clinical enzymology studies enzymes in blood to diagnose diseases. Some enzymes are normally present in the blood, while others are released only when tissues are damaged.

Different forms of Lactate Dehydrogenase (LDH) with varying affinities for the substrate. They are also affected differently by activators and inhibitors.

Enzymes released into the bloodstream when heart muscle is damaged, indicating a heart attack. These enzymes include Creatine Phosphokinase (CPK), Aspartate Transaminase (AST), and Lactate Dehydrogenase (LDH).

Enzymes released from damaged liver cells, aiding in diagnosis of liver conditions. They are categorized into two types: those reflecting damage to hepatocytes (liver cells) and those reflecting cholestasis (bile flow blockage).

An enzyme mainly found in the liver, released into the blood when liver cells are damaged. It is a more specific indicator of liver damage compared to AST.

An enzyme present in various tissues, including the liver and heart. Elevated levels can suggest liver damage, but also heart problems.

An enzyme often elevated in cases of cholestasis, a condition where bile flow from the liver is blocked. It can also be increased in bone disorders.

An enzyme primarily found in the liver, primarily elevated in cases of cholestasis, like alkaline phosphatase.

An enzyme used in tests to measure urea levels in the blood. Urea is a waste product from protein metabolism.

An enzyme used in tests to measure glucose levels in the blood. Glucose is the primary sugar used by the body for energy.

Enzymes can be used as medications to treat various conditions, for example, dissolving blood clots (Streptokinase/Urokinase), aiding digestion (Trypsin, Lipase, Amylase), and reducing inflammation (Papain, Chymotrypsin).