Proteins by the Numbers

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We couldn’t survive without proteins. They’re essential molecules that provide cells with structure, aid in chemical reactions, support communication, and much more. Portion out protein numbers with us below!

Cells shown as circles outlined in red with bright green spots inside many of them.
These green spots are clumps of protein inside yeast cells that are deficient in both zinc and a protein that prevents clumping. Credit: Colin MacDiarmid and David Eide, University of Wisconsin at Madison and the Journal of Biological Chemistry.

10 Trillion

That’s how many proteins scientists estimate are in each human cell.

229,378

That’s how many structures researchers shared with the scientific community through the Protein Data Bank (PDB) from its establishment in 1971 to the end of 2024. The PDB is a global repository for 3D structural data of proteins, DNA, RNA, and even complexes these biological molecules form with medicines or other small molecules.

42

That’s the percent of your body weight (not counting water) that’s made up of proteins.

Three protein structure illustrations: 1) differently colored beads on a string; 2) the string twisted and folded; and 3) a large, amorphous structure representing a folded protein.
Proteins are made of amino acids hooked end to end like beads on a necklace. To become active, the necklace must twist and fold into its secondary, tertiary, and sometimes quaternary structure. A protein’s final shape enables it to accomplish its function. Credit: NIGMS.

4

That’s the number of different levels of protein structure:

  1. Primary, the order of the amino acids in the chain
  2. Secondary, the way those amino acids interact with one another either as helices or pleated sheets
  3. Tertiary, the way that chain of amino acids folds to take on a 3D shape
  4. Quaternary, interactions between multiple proteins

50

That’s, on average, how many nucleotides a human RNA polymerase, a type of protein, condenses into a messenger RNA (mRNA) molecule each second. That means an average gene takes about 10 minutes to transcribe from DNA to RNA.

On the left is a DNA molecule with its two halves separated. One half has a matching mRNA strand. On the right, an mRNA strand passes through a ribosome with a tRNA molecule, connecting it to a string of amino acids. These amino acids then become the newly synthesized protein.
DNA encodes RNA, which encodes protein. DNA (blue strand) is transcribed to make mRNA (dark red strand). The mRNA sequence is complementary to the DNA sequence. Ribosomes read three mRNA nucleotides at a time to join the appropriate amino acids together to make a protein. Credit: NIGMS. Click to enlarge.

10

That’s about how many amino acids a human ribosome adds into a growing protein every second. This process is called translation.

1

That’s how many minutes it takes for a ribosome to make an average-sized protein. But multiple ribosomes can read the same mRNA molecule at the same time. They space out along the mRNA chain every 100-200 nucleotides for simultaneous translating, each functioning independently to produce its own chain of amino acids.

140

Ribosomes depicted as two large, blue blobs with a purple-beaded string of mRNA on the bottom and a red-beaded string of proteins on the top, connected by a brown blob of tRNA molecules.
Ribosomes (blue) manufacture proteins (red) based on mRNA (purple) instructions. Each ribosome reads mRNA, recruits tRNA molecules (brown) to fetch amino acids, and assembles the amino acids in the proper order. Credit: Judith Stoffer.

That’s the average number of proteins that ribosomes can make from a single mRNA molecule per hour.

22

That’s how many amino acids researchers have found to be encoded in genes. You may be familiar with 20 of them, but the last two are fairly new to the lineup: selenocysteine (a cysteine with a selenium atom instead of a sulfur atom) and pyrrolysine (a derivative of lysine that’s currently only been found in some types of bacteria and archaea, not in humans). But if we count all the different types of amino acids found in proteins, the number is over 400! That’s because proteins get modified after translation with different chemical groups, like the addition of methyl or ubiquitin groups. These post-translational modifications play a role in regulating protein activity by affecting their structure and function.

A type of protein shown as several bundles of ropelike strings.
Researchers used scanning electron microscopy to capture this image of collagen, a strong, ropelike molecule that forms stretch-resistant fibers. Credit: Tom Deerinck and Mark Ellisman, National Center for Microscopy and Imaging Research.

30

That’s the percentage of all proteins in your body that are collagen. As the main building block for your skin, muscles, bones, and connective tissues, it’s the most common protein in your body.

60

That’s how many microns per second myosin—the protein in your muscles—can move. A micron is one millionth of a meter, so while 60 per second may not seem very fast, don’t forget we’re talking about tiny proteins. To be as fast as myosin, relatively speaking, an average adult human would need to run at a speed of about 1,300 miles—the distance from Washington, D.C., to Dallas, Texas—per hour!

153 

That’s the number of amino acids in myoglobin—the first protein structure researchers ever deciphered. When they solved how the amino acids fit together in 1958, it revealed how protein chains fold and interact with one another. Knowing the structure of myoglobin helped researchers understand how it stores oxygen in muscle cells. This structure, and several other oxygen-carrying protein structures, were some of the first in the PDB.

34,000

A bright blue matrix connecting numerous black circles.
Myosin (blue) gathers at the edges of fertilized fruit fly egg cells (black) as their nuclei divide. Credit: Victoria Foe, University of Washington.

That’s the number of amino acids in titin, one of the largest proteins in your body. Titin acts like a giant rubber band to give muscles their elasticity.

For more details on the synthesis and function of proteins, check out our post “Science Snippet: The Power of Proteins,” and if you liked this post, catch our other “By the Numbers” posts!

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