What You Should Know About Proteins

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Different Roles of Proteins in the Human Body

What do proteins do? Are all proteins the same, with similar functions in the body? Not at all—proteins have a wide variety of functions in the human body, from building and repair of muscle tissue, to keeping skin and hair healthy. In fact, almost all chemical reactions in the body require one or more proteins.

Protein Metabolism: What Happens to “Old” Proteins?

In the healthy human body, most proteins are reused or recycled, and little protein ends up as waste in urine. In some cases, however, the human body processes proteins abnormally, with the result that levels of protein in urine are higher than normal. A high level of protein in urine is a symptom of many diseases, including diabetes and rheumatoid arthritis.

The Molecular Structure of Proteins

This article provides more information about protein structure and how it relates to protein function, as well as the significance of a protein’s amino acid sequence.

How is Protein Structure Determined?

Protein structure is classified at four different levels, mostly in reference to the three-dimensional structure of each individual protein type. Several different methods can be used to determine the 3D structure of a protein, with the most common one being crystallography. In this article you will learn about crystallography and other methods of determining the structure of proteins.

Methods for Sequencing Proteins

Several different methods can be used to determine the amino acid sequence of a protein. Learning this type of information is important because the sequence of a protein determines its three-dimensional structure, and both of these aspects of a protein help determine how it interacts with other molecules. This article outlines protein sequencing methods such as mass spectrometry and the Edman degradation process.

The Endoplasmic Reticulum: An Important Site for Protein Function and Endoplasmic Reticulum FAQ

The endoplasmic reticulum, or ER, is an organelle (a “mini organ”) which is a critical site for protein activity. Proteins are manufactured and folded within the rough endoplasmic reticulum, so-called because it is studded with ribosomes, tiny molecular units that interact with proteins as they are being formed and folded.

Read about Ribosomes and Structure & Function of Ribosomes

Ribosomes are the cellular protein factories. Within ribosomes, messenger RNA sequences are used as templates for constructing new proteins.

All About Albert Claude, the Scientist who Discovered the Endoplasmic Reticulum

Albert Claude won a Nobel Prize for his work on the endoplasmic reticulum, but his was certainly an unconventional road to success. This renowned scientist was a high-school dropout from a remote Swiss town, and was a British secret service agent during World War I!

The Golgi Apparatus, Another Important Protein-Manufacturing Site

After newly formed proteins are manufactured in ribosomes, they are modified in a new set of organelles called the Golgi apparatus, or Golgi bodies. Many proteins are modified post-production with the addition of chemical groups that facilitate their activity within the body. Once the proteins have been modified, they are “delivered” to their proper locations.

Enzyme Reactions and Functions

Enzymes are proteins that speed up chemical reactions in the body. They are catalysts, which means they accelerate the rate at which reactions occur, but are not themselves part of the reaction. There are several thousand known enzymes, and more than 4,000 known reactions in the human body that use enzymes. This article explains what enzymes are, and how they are thought to work.

Protein Functions: C-Reactive Protein

C-reactive proteins, or CRPs, are part of the inflammatory response that develops in response to infection and injury. High levels of these proteins are present in blood only during the inflammatory response, and for this reason CRP levels are a good indicator of the presence of infection.

Protein Functions: Digestive Enzymes and The Rennin Enzyme

Digestion takes place via enzyme reactions that break up food into its constituent molecules: protein, fat, and carbohydrates. Various types of these macromolecules are digested by different enzymes. In the case of milk, for example, one of the enzymes for digestion is called rennin. Rennin is widely used in the dairy industry, specifically in cheese production.

Use of Proteins in Science: Restriction Endonucleases

These protein enzymes were discovered in the 1970s by scientists Werner Arbor, Dan Nathans & Hamilton Smith. Restriction endonucleases were found to be enzymes that cleave DNA at specific base-pairing sites, and this feature of the proteins has made them enormously useful in molecular biology and biotechnology.

What is “De Novo” Protein Design?

Understanding the four different levels of protein structure, and how proteins interact with other molecules, has given rise to a new field of science, known as de novo protein design, literally, the design of new proteins.


  • This is a compilation of articles contained on the Bright Hub site. References and resources used by the authors to create each piece of content within the compilation can be found on the individual articles themselves.