Login with Facebook

All you need to know about metabolic pathways

Metabolism is the set of chemical transformations that take place in living organisms

The highly coordinated cellular activity allows you to:

- obtain chemical energy from the environment (sunlight or degradation of nutrients)

- converting nutrient molecules into monomeric molecules, characteristic of the cell itself

- synthesize polymers (proteins, nucleic acids, lipids, polysaccharides) from monomeric precursors

- Synthesize and degrade the cell's typical biomolecules (lipid membranes, cell messengers, etc.)

Do you want to get written your assignment? Order now for cheap reliable essay writing service.

The metabolic pathways

It is an ordered sequence of reactions catalyzed by enzymes.

In a metabolic pathway, a precursor molecule is converted into a product through a series of intermediates (metabolites).

CATABOLISM → degrading phase of metabolism: molecules derived from nutrients are converted into simpler final products, energy is released.

ANABOLISM → phase of biosynthesis of the metabolism: the simplest precursors are converted into biological molecules; it requires energy.

The metabolic pathways can be linear or nonlinear (convergent, divergent, or cyclic).

- In the metabolic pathways converging from different precursors, a single final product is generated

- In the ways diverging from a single precursor, there are different end products

- In the cyclic pathways, one of the starting molecules is regenerated, another is converted into the final product

Energy relations between the metabolic pathways

The catabolic pathways oxidize nutrient molecules and produce free energy in the form of:

1. Adenosine triphosphate ( ATP )

2. Electron conveyors in reduced form ( NADH, NADPH, FADH 2 )

3. Heat

4. The anabolic pathways use energy for the synthesis of biological molecules: This occurs due to the transfer potential of the phosphoric group of ATP and the reducing power of NADH, NADPH, and FADH 2.

Regulation of metabolic pathways

The control of the metabolic pathways takes place through the coordinated modulation of catabolism and anabolism. The main mechanism consists of the separate regulation of the sequences of catabolic and anabolic reactions (if one way works, the other is blocked and vice versa). In the catabolic and anabolic pathways which share the same starting compounds or end products, at least one stage is catalyzed by different enzymes, which are therefore subject to separate regulation. The anabolic and catabolic pathways that connect the same compounds have different intracellular locations.

Levels of regulation of the metabolic pathways: availability of the substrate

The substrate concentration influences the initial velocity (V 0) of an enzymatic reaction, according to the Michaelis-Menten equation.

Often the physiological concentration of the substrate is close to the Km values, so small variations of [S] involve considerable variations in the speed of reaction (first-order reaction).

Levels of regulation of the metabolic pathways: regulatory enzymes

The enzymes of a certain metabolic pathway work in sequence and most follow the Michaelis-Menten model described.

One or more enzymes (regulatory enzymes) can increase or decrease their catalytic activity in response to certain stimuli. In many metabolic pathways, the first enzyme in the sequence is a regulatory enzyme.

Regulatory enzymes

There are two classes of regulatory enzymes:

1. Enzymes regulated by reversible covalent modifications

2. Allosteric enzymes: they bind to molecules, called allosteric modulators or effectors, with the non-covalent and reversible bond.

Allosteric modulators can be inhibitors or activators.

The regulatory enzymes typically are positive, whose substrates also behave as modulators (homotropic).

Regulatory enzymes whose substrates do not act as modulators are called heterotopic (they can be positive or negative).

Allosteric Enzymes

Allosteric regulatory enzymes contain two or more subunits.

Besides the catalytic sites (C), one or more regulatory or allosteric sites are present, generally on different subunits (R) for the binding of the modulators (inhibitors or activators).

Allosteric enzymes undergo conformational changes induced by the binding of the modulator VARIATION of the enzymatic activity.

Kinetic properties of allosteric enzymes

Allosteric regulatory enzymes have kinetic properties that differ from the Michaelis-Menten model described.

In the case of a homotropic enzyme, in which the substrate also acts as a positive modulator, the curve is of the sigmoid type (Km is replaced by K 0.5).

The kinetics of heterotropic regulatory enzymes (modulator other than the substrate) is modified by the presence of activator or inhibitor

(a) The sigmoid curve in the presence of an activator becomes more similar to a hyperbolic curve, while in the presence of an inhibitor it becomes more sigmoid in this kinetics it does not change V max but K 0.5.

(b) For other regulatory enzymes, there is kinetics in which only the V max varies.

Allosteric enzymes: Cooperativity

The sigmoid curve is caused by the cooperative bonding of the substrate.

Remember that the binding of O 2 to the heme of Hb subunit (which is not an enzyme) facilitates the binding of other O 2 molecules to the heme groups of the other subunits → POSITIVE COOPERATIVE EFFECT.

Sigmoid kinetics can be explained on the basis of two models:

(a) Concerted model - Monod model, Wyman, and Changeux.

 The enzyme exists in two conformational states:

- Thelow affinity and high affinity are in balance with each other. The ligand binds the O state more easily, removes the shape from equilibrium, and this increases the affinity for the substrate

(b) Sequential model - Koshland model:

The various subunits can take on different conformations:

- low affinity or high-affinity O

The bond with the substrate induces conformational modifications that facilitate the passage of the other subunits from to O.

This model explains both positive and negative cooperativity.

Inhibition of feedback

In some metabolic pathways, an intermediate, often the end product, functions as an allosteric inhibitor of the first enzyme that regulates the pathway.

In this way, the downstream enzymes work at a reduced speed due to a lack of substrate, the quantity of the final product adapts to the needs of the cell.

The bacterial multi-enzyme system that converts L-threonine to L-leucine is an example.

Branched metabolic pathways: regulation

The regulation of branched metabolic pathways is based on:

1. presence of isoenzymatic forms (enzymatic multiplicity) if the products of the same route are required for other routes

2. sequential feedback

3. cumulative feedback

4. multivalent feedback

5. synergic feedback

Enzymatic regulation: reversible covalent modifications

The activity of many enzymes is regulated through reversible covalent modifications on one or more amino acid residues.

The modification reactions are decisive for the enzymatic function; they regulate its affinity for the substrate (increase or decrease).

These changes are inserted or removed by other enzymes.

Among the numerous modification reactions (> of 500), the most common are: phosphorylation, acetylation, adenylation, myristoylation, ubiquitination, ADP-ribosylationCatabolic Anabolic, methylation. The most important type of covalent regulation is phosphorylation/dephosphorylation.

Author: Vicki Lezama

Need a custom

We will write it for you.
Order now

Free Essay Examples

Free essays:

All you need to know about Neuroendocrinology
All you need to know about Big data management
All you need to know about digital special effects
All you need to know Technical Writing?
Basics the Game Theory in Cryptoeconomics
Business innovation ideas for making money
Biosensors for cancer diagnosis
Business Analysis: Pricing strategies and Demand Curve
Cognitive Computing- How does Cognitive Computing work?
Consciousness: characteristics and peculiarities
Conservation Economics
Cybersecurity in business: challenges, risks, and practices
Demographic trends and how they affect Economic Growth
Dance as an art form and entertainment
Discrimination Economics
Determinants of Wages
Everything you need to know about short-term memory
Economic and Policy Impacts of Demographics
Ethics: an essay on the understanding of evil
Emotions: what are they? Theories explained
Factors of Demographic Data Collection
Factors Affecting Purchasing Behavior
Financial Statement Analysis
Factors Influencing Interest and Exchange Rates
Government's Intervention in The Labor Market
Guide on the Pathways of the nervous system
Game theory in microeconomics
Globalization: definition, causes, social impact and risks
How Relativism Promotes Pluralism and Tolerance
How to use the audience’s feedback to write a news report
History of silent cinema
How news report can be strengthened through multimedia
Introduction to Population Problems
Imperfect Information and Asymmetric Information
Imperfect Information in Insurance
Introduction to Labor Markets
Journalism: What is News?
Journalism: Broadcast media and Television Presenters
Journalism: Sources of News
Journalism and Law
Key Determinants of National Income
Key Factors That Affect Pricing Decisions
Kinetic models in biology and Related fields
Know about the different forms of traditional African dances
Latest technology trends
Latest dance trends
Magnetoencephalography (MEG)
Microeconomic Analysis to the Demand for Labor
Neuromuscular disorders
National Economies, Fluctuation, and Responses to Fluctuations
Neurotransmitters: what they are and different types
Nanomedicines to target tumors
Objections to utilitarianism
Organizational motivation and its effects
Overcoming Hiring Challenges for Nonprofit Organization
Population Demographics
Recurrent neural networks (RNN) for speech detection
Russian School of Mathematics
Research and Development
Risk Sharing in Insurance and Asset Markets
Stochastic optimization methods in deep learning?
Structure of the nervous system
Structure of a Corporation
Schizoaffective disorder: how to live better with it
The climate change denial
The techniques of basic cinematography
The Endosymbiotic Theory
The Role of Internal Audit in Corporate Risk Management
Utilitarianism Vs. Kantianism
Understanding Auctions and Auction Theory: Part 2
Various theoretical perspectives of sociology
Virtual reality, what it is and how it works
What are the linear models in machine learning?
What is Convolutional Neural Network
4 Facts about Origin of Mathematics!
5 techniques to create an animation
10 emerging technologies according to World Economic Forum
10 strategies to maximize corporate profits
3d Model Of Building
6 Medical Technologies that revolutionized the healthcare in 2020
All you need to know about the ACA Code of ethics
Architecture and Democracy: An Introduction
Architecture and Democracy: Democratic Values
Architecture and Democracy: Democratic Procedures
All You Need to Know About a Synthesis Essay
An essential guide to understanding Film Theory
Application of Artificial Intelligence in Cyber Security
Applications of electrical engineering
Augmented reality: what it is, how it works, examples
Advantages And Disadvantages Of Social Networking
All you need to know about Cryptography
Applications of astrophysical science
All you need to know about architecture engineering
Applications of geological engineering
Artificial intelligence and medicine: an increasingly close relationship
An insight into Computational Biology
ACA code of conduct
A Rose for Emily
Applications of Mathematics in daily life
Architecture mistakes to avoid
All you need to know about Toxicology
All you need to know about Holistic Medicine
All you need to know about linguistics
An introduction to Linguistics and its subfields
All you need to know about Anxiety disorder
All you need to know about Drones
A Brief Insight into Political Science
Assumptions related to feminism
All you need to know about Byzantine emperors
All you need to know about labour economics
An insight into xenobots -the first-ever robots
An ultimate guide about Biomaterials
A Comprehensive Introduction to the Mona Lisa
Analysis methods of Transport through biological membranes
An ultimate guide about biochemical reactions
Analysis of brain signals
Artificial Gene Synthesis
Application to synthetic biology of CAD methods
All you need to know about metabolic pathways
Applications of BIOMEMS
All you need to know about the epidemiology
Asian vs. western leadership styles
All you need to know about Smart prosthesis
Analysis of Economy: Output of Goods and Services (GNP), and GDP on Economic success
A Guide to Pricing Strategies
An Overview Of Economic Studies
Analysis of Fiscal and Monetary Policies
Analysis of Business Cycles
Analysis of Consumption and Investment
A Look into Regression Analysis
Analysis of Household's Consumption and Savings Behavior
All you need to know about Capital Budgeting
All you need to know about risk management
Art looted in wartime.
Appropriate use of Data in Economics
All you need to know about reaction kinetics?
A historical overview of Financial Crises
All you need to know about management discipline?
An insight into the error-correction models
All you need to know about Data visualization
All you need to know about Work-family balance
All you need to know Technical Writing?
All you need to know about digital special effects
All you need to know about Big data management
All you need to know about Neuroendocrinology
How to Write a Personal Essay
Housing Needs in America
How to Write a Description Essay
How to Create an Excellent Scholarship Essay?
How to write a cause and effect essay
How to Hire the Best Essay Writing Service Provider?
How to Write a College Application Essay?
How to get the most out of your English lectures
How to write Expository Essay
How to succeed in your psychology class?
How to Write an Academic Essay in the Shortest Time?
History of Journalism
How Different Sectors are Using Artificial intelligence (AI)
How to write an informative essay
How to deliver persuasive essays?
How to Give a Convincing Presentation
How to write an essay on leadership?
Historical Art Still Around Today
Humanoid robot: what it is, how it works and price
History of Chemistry
Healthcare Advanced Computer Power: Robotics, Medical Imaging, and More
Healthcare AI: Game Changers for Medical Decision-Making and Remote Patient Monitoring
How to understand different types of English
How to Cope with Chronic Pain
How African American choreographers and dancers have influenced American dance
How mobile robot can do in logistics or in production
How To Become a Successful Entrepreneur
History of the Philosophy of Feminism
How is the climate changing?
How to Track Your Content Marketing ROI
How to Gun control In the USA?
Historical and contemporary role of labour in the modern world
How breast cancers are classified?
How the cells of our body communicate?
How the Lymphatic System Works?
How Digestive System Works
How to complete your capstone projects effectively?
How to write a research project
Healthcare technologies that help patients with better self-management
How to choose the topic of the senior capstone project
How to make your business survive at economic crisis
How can immigrants blend in the American society?
How does the economics of war affect society?
Hate speech on social media.
How to Build an Economic Model
How to start a healthcare startup?
How can financial illiteracy harm you?
How cancer is developed - Cancer biology
How to define the Enterprise Value
How to conduct economic research?
How women can manage sexual harassment
How to use quotes in your news reports?
How news report can be strengthened through multimedia
History of silent cinema
How to use the audience’s feedback to write a news report
How Relativism Promotes Pluralism and Tolerance
Introduction to Urban Studies
Importance of dance in education
InMoov: how to build an open source humanoid robot
Importance of KYC verification to making the Blockchain secure
Importance of Rhythm
Importance of dance student evaluation
I/O control methods -types and explanations
Identity theft: what to do?
Introduction to Utilitarianism
Importance of 3d Modelling in Architecture
Importance of online journalism
Image processing in medical diagnosis
Introduction to USA Politics
Introduction to Comparative Politics
International Relations as a Major in Political Science
Importance of modern trade policy
Introduction to Journalism
Introduction to Writing a TV Script
Introduction of Microfabrication techniques
Introduction to Microeconomics
Interaction of Consumer and Firm Choices in Markets
Importance of corporate sustainability
Issues in International Monetary Macroeconomics
Introduction to Statistics and Data for Economics
Introduction to Data and Probability for Economics
Introduction to the Game Theory
Introduction to Econometrics
Introduction to Economic Information
Introduction to Market Equilibrium
Introduction to Economic Models and Application
Introduction to Empirical Research
Introduction to Econometric Data
Importance of Critical Thinking, Principles, and Goals
Introduction to Identification and Causal inferences
Introduction to Econometric Application
Intermediaries and Government in Financial Crisis
Importance and seven principles of quality management
Illiteracy in the USA
Introduction to Economics of Law
Introduction to Coase Theorem
Introduction to Social Choice and Incarceration
Intellectual Property and Product Liability
Investment in Human Capital
Introduction to Labor Markets
Imperfect Information in Insurance
Imperfect Information and Asymmetric Information
Introduction to Population Problems
The Looming Energy Crisis in America
Top benefits of performance-based engineering
The More Languages You Know, The More Times You Are a Man
Things to consider while writing an Argumentative Essay
Top Ways to Improve Your Academic Writing Skills
Tips to Excel in Creative Writing
The origins of films in the early 19th century
Top career options in Architecture
The Elevator Pitch
Top finance trends 2020
The basic Structure and functionality of robots
The Way to Success
The election system of the President in the United States of America
Two-party System in United States of America
Top trends in urban design
The history and theory of African American filmmaking
Top benefits of creative writing
Tinnitus Guide: Common Symptoms and Treatment Options
The language of dance
The digital image processing management
Top famous politicians of the World
Top methods of political science!
The history of the feminist movement
The blood flow in cardiovascular system - Biofluid Mechanics
The best of Leonardo Da Vinci
The Structure and Function of Macromolecules
The structure of cell: a research on the bricks of the human body!
Tissue and organ construction: Adhesion and recognition between cells
The kinetics of the transformation processes
The Modeling of Biological Systems
Tips for writing a great thesis statement
The Defense mechanisms against infections
The impact of the technological innovations in medicine
Top journalism trends to know about
The relation between mass media & politics
Theranostics: Diagnosis and Care through Nanoparticles
The practical Applications of X-rays
The applications of Ultrasound in medicine
Transfer mechanisms of genetic information in Bacteria
The regulation of cellular metabolism in the diagnosis
The Principles of MRI Contrast agents
The technical basis of optical coherence imaging
The New Media: Emerging Trends
The Structure of Interest Rates and the Yield Curve
Technological perspectives and reflections of neural engineering
Types of bioreactors and their applications
The Role of Government Policy in Improving Economic Outcomes
Types of corporate responsibility
The Role of IMF in International Monetary Macroeconomics
Tools for investment decision making
The concept of Organizational Culture and its applications
The Conduct of Monetary and Fiscal Policy
The Basics of Financial Accelerator Models
Tips for labeling medical devices- Medical Entrepreneurship
The different medical imaging techniques
The Economics of Uncertainty – Introduction
Theories of Public Policy
The Game Theory in Social Media
The political theory of Thomas Hobbes
The Use of Law on Economics and Vice Versa
The Role of Internal Audit in Corporate Risk Management
The Endosymbiotic Theory
The techniques of basic cinematography
The climate change denial
What is a Definition Essay?
What are diagnostic essays?
What is the relation between art structural engineering?
What is a Narrative Essay
What are robotics and intelligence systems?
What are the benefits of studying health sciences?
What is artificial intelligence and why it matters?
What is comparative Literature?
Why study neuroscience
What is Wi-Fi and how does it works
What is French history famous for?
What are Humanistic Studies?
What is covered in Biophysics?
What is modern journalism?
What is Virtualization? Benefits & Applications
What are modern public relations?
What is plasma physics?
What is teacher preparation?
What is rapid prototyping for 3D printing?
What is contemporary European Politics?
Why should you learn American Ballet?
What is engineering physics?
What is the purpose of African American Literature?
Ways to learn the Rhythm
What is digital art used for?
What are Enzymes and how do they work
Who is the father of political science?
Why Study Political Science - Job?
What is the Philosophy of Feminism?
What is a quantum computer?
Ways B2B Startups Streamline Their Conversion Strategies
Why do biomedical signals need processing?
What are the long term effects of climate change?
Why study labour relations
What is Holoprosencephaly?
What is antisocial disorder?
What are the important principles of evolution?
What is the cytoplasm and its function?
What is biopolymers?
What Makes a Good Leader
Women empowerment in modern generation
What is the history of political thought?
What is Gene recombination
What is synthetic biology
What is business cost analysis?
What is Inflation
What are the consequences of unemployment?
What is lithotripsy and its types?
What is transition elastography?
What is the purpose of deep brain stimulation?
What is a Brain-Computer Interface (BCI)
What is neuroethics?
What is Market and Supply and Demand
What is optogenetics?
What are the techniques to record brain activity?
What happens if the interest rate increases?
What is immunotherapy?
What is the economic role of the financial market?
What are the factors behind illegal immigration?
What is the lymphocyte activation?
What is financial market and its types?
What is the structure of financial markets?
What are the methods of measuring business performance?
What is the Credit market?
What is business ethics and code of ethics
What are the Causes of financial instability?
What is MBA with Concentrations
What is regenerative medicine?
What is Population ecology?
What is Microfinance: evolution, and practices?
What is biotechnology and its applications?
What are Workplace diversity and its benefits?
What is the difference between a leader and a manager?
What Is Branding and best branding Business strategies?
Why are microelectronics important?
What are biologic drugs.
What is the Foreign Exchange market?
What is the role of scientific research in times of crisis?
What are the risks of international trade?
What is financial management?
What is gene therapy?
What is education economics?
What is regression analysis, and why should you use it?
What Is Technology Marketing And How Should It Work?
What is Management Accounting
What are the methods of valuation of companies?
What is Immune System and Immunotherapy?
What is big data analytics?
What is the 7 layers of OSI model?
What is Neuroplasticity?
What are Sculpture art and its types?
What are the different genres of films?
What is Transcranial magnetic stimulation (TMS)?
What is TES-Transcranial electrical stimulation?
What is Relativism?
What is Vaccine skepticism, and what to do about it?
What happens in the brain when learning?
What is the deep neural network?
What is Convolutional Neural Network
What are the linear models in machine learning?