Kaj Ulrik Linderstrøm-Lang facts for kids

Kaj Ulrik Linderstrøm-Lang (born November 29, 1896 – died May 25, 1959) was a Danish scientist. He studied proteins and led the Carlsberg Laboratory from 1939 until he passed away.

Kaj Linderstrøm-Lang made big discoveries about proteins. He found new ways to study how proteins are built and how they work. He also defined the four main levels of protein structure: primary, secondary, tertiary, and quaternary.

He loved studying proteins and taught many future scientists. His lab was a fun place, known for great Christmas parties and trips to the Tivoli amusement park. Kaj was also a writer, musician, and storyteller. He even helped in the resistance movement against the Nazi occupation of Denmark.

Exploring Proteins: Kaj's Research

Starting in Science

Kaj Linderstrøm-Lang first studied physics. He joined the Carlsberg Laboratory, working with S. P. L. Sørensen, who invented the pH scale. Kaj helped define the "isoionic point" for proteins. This describes when a protein has no overall electrical charge.

Clever New Methods

One of Kaj's smartest ideas was the "Cartesian diver" method. This helped measure how dense tiny things were. He used a long tube with different oils. A small drop with proteins would float down until it reached an oil with the same density. This allowed him to see very small changes, like when an enzyme was working.

Understanding Hydrogen Exchange

Kaj Linderstrøm-Lang is known as the "father" of hydrogen–deuterium exchange. This method helps scientists learn about the shape and movement of proteins. It works by swapping hydrogen atoms in a protein with heavier deuterium atoms. This helps show which parts of a protein are exposed to water.

The Four Levels of Protein Structure

Kaj Linderstrøm-Lang is famous for explaining how proteins are organized. He described four levels of protein structure:

• Primary structure: This is the simple chain of amino acids. Think of it like the order of letters in a word.
• Secondary structure: This is how the amino acid chain starts to fold into basic shapes. Common shapes are spirals (called alpha-helices) or zig-zag sheets (called beta-sheets).
• Tertiary structure: This is the full 3D shape of a single protein molecule. It's how all the spirals and sheets fold together.
• Quaternary structure: This level is for proteins made of several smaller protein units working together. It's how these different units fit to form a larger complex.

He shared these ideas in lectures at Stanford University in 1951.

Helping Other Scientists Grow

Kaj Linderstrøm-Lang taught and inspired many important protein scientists. Some of his students included Frederic M. Richards and Christian B. Anfinsen. He also had a key idea about how "hydrophobic interactions" work. These are forces that make water-hating parts of proteins clump together. He realized these forces depend on more than just energy.

Awards and Special Honors

Kaj Linderstrøm-Lang received many awards for his work. He became an international member of the United States National Academy of Sciences in 1947. He was also honored by the American Academy of Arts and Sciences in 1950. In 1951, he joined the American Philosophical Society. Finally, in 1956, he became a Foreign Member of the Royal Society in London.