Drug discovery

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Biotechnology in Medicine

Chapter 12

Learning Outcomes

 Discuss the scope and role of medical biotechnology in the healthcare industry

 Explain the function of drugs and discuss how they may be created using combinatorial chemicals

 Describe the various high-throughput screening processes for potential drug activity

 Explain the methods for synthesizing peptides and oligonucleotides and discuss the uses of each

 Detail the multiple uses of antibodies in medical biotechnology and discuss the immune response that results from vaccinations

12.1 Drug Discovery

Medical biotechnology includes R&D in the following areas:

• Causes of diseases and disorders

• Drugs, pharmaceuticals, and medicines derived from nature or through genetic engineering and/or combinatorial chemistry

• Disease prevention, vaccines, and gene therapy

• Diagnostics for medical applications

• Prosthetics or instruments for replacement or improvement of tissues and organs

Drug Development

Drugs are chemicals that alter the effects of proteins or other molecules associated with a disease-causing mechanism

A drug is usually specific for a particular disease process

Sources of Potential Drugs

The drug discovery process may involve finding chemical compounds that show activity against one or more molecules associated with a disease.

The process is lengthy and often tedious.

Vocabulary

Medicine – something that prevents or treats disease or alleviates the symptoms of disease

Medical biotechnology – all the areas of research, development, and manufacturing of items that prevent or treat disease or alleviate the symptoms of disease

Drug – chemical that alters the effects of proteins or other molecules associated with a disease-causing mechanism

Drug discovery – the process of identifying molecules to treat a disease

Organic synthesis – the synthesis of drug molecules in a laboratory from simpler, preexisting molecules

Screening – the assessment of hundreds, thousands, or even millions of molecules or samples

Pathogenesis – the origin and development of a disease

Combinatorial chemistry – the synthesis of larger organic molecules from smaller ones

12.1 Review Questions

1. What kinds of organisms cause diseases?

2. Where are drugs typically discovered?

3. How is aspirin an example of combinatorial chemistry?

12.2 Creating Pharmaceuticals through Combinatorial Chemistry

Natural compounds must sometimes be modified to be more useful or effective.

Techniques for Creating New Drugs

Combinatorial chemistry is the process of creating new and varied organic compounds by linking chemical building blocks.

Screening Compounds

Some drug screening must take place in animal or human cells.

Most can be screened on sophisticated instruments.

Vocabulary

Parallel synthesis – making large numbers of batches of similar compounds at the same time

Library – a collection of compounds, such as DNA molecules, RNA molecules, and proteins

Biochip – a special type of microarray that holds thousands of samples on a chip the size of a postage stamp

Microarray – a small glass slide or silicon chip with thousands of samples on it that can be used to assess the presence of a DNA sequence related to the expression of certain proteins

12.2 Review Questions

1. What is the value of combinatorial chemistry?

2. How are chemical compound libraries related to high-throughput screening?

3. What is the value of microarray technology?

12.3 Creating Pharmaceuticals through

Peptide and DNA Synthesis

A peptide can be used in an attempt to identify regulator molecules.

A peptide may be used as a vaccine antigen to initiate an antibody response.

Peptides are often synthesized for use in the purification of other proteins.

Oligonucleotide Synthesis

Scientists have learned to make small pieces of DNA, called oligonucleotides.

Vocabulary

Peptides – short amino acid chains that are not folded into a functional protein

Peptide synthesizer – an instrument that is used to make peptides, up to a maximum of a few dozen amino acids in length

Oligonucleotides – segments of nucleic acid that are 50 nucleotides or less in length

DNA synthesizer – an instrument that produces short sections of DNA, up to a few hundred base pairs in length

12.3 Review Questions

1. What are three uses of peptides in medicinal biotechnology?

2. How does a peptide synthesizer make peptides?

3. How does a DNA synthesizer make oligonucleotides?

4. Of what value are oligonucleotides?

12.4 Creating Pharmaceuticals by

Protein/Antibody Engineering

Large proteins can be synthesized through genetic engineering.

Antibodies are the most complicated of all proteins.

Using Antibodies to Purify Proteins

Antibodies are often needed in large quantities.

Using Antibodies to

Recognize Molecules

Antibodies may be used to recognize molecules in medical research applications.

Using Antibodies and

Antigens in Vaccines

Antibody-antigen reactions are important in disease prevention.

Vocabulary

Slow cytometry – a process by which cells are sorted by an instrument, a cytometer, that recognizes fluorescent antibodies attached to surface proteins on certain cells

Vaccine – an agent that stimulates the immune system to provide protection against a particular antigen or disease

B-cells – specialized cells of the immune system that are used to generate and release antibodies

Memory cell – a specialized type of B-cell that remains in the body for long periods of time with the ability to make antibodies to a specific antigen

Immunity – protection against any foreign disease-causing agent

12.4 Review Questions

1. How are antibodies used in flow cytometry?

2. How does a vaccine increase the number of antibodies in a person?

3. How does a vaccine provide immunity?

Questions and Comments?

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