light chain

American  

noun

1. Immunology. either of an identical pair of polypeptides in the antibody molecule that lie parallel to the upper parts of the heavy chain pair and are half the molecular weight.

---

light chain Scientific  

1. The smaller of the two types of polypeptide chains in an antibody molecule. A light chain consists of an antigen-binding portion with a variable amino acid sequence, and a constant region with an amino acid sequence that is relatively unchanging. The light chains are attached to the heavy chains so that the variable regions of both lie alongside each other.

2. Compare heavy chain

---

Etymology

Origin of light chain

First recorded in 1960–65

Example Sentences

These included tau and amyloid beta proteins, neurofilament light chain proteins and glial fibrillary acidic proteins.

From Science Daily • Dec. 5, 2025

Roughly a year later, they observed a rise in neurofilament light chain, a marker of injury to the nerve fibers themselves.

From Science Daily • Oct. 21, 2025

What enzyme is responsible for the random excision of variable gene segments making up an antibody light chain in DNA?

From Textbooks • Jun. 9, 2022

The heavy chain and the light chain are the two polypeptides that form the antibody.

From Textbooks • Jun. 19, 2013

Naomi pulled the light chain, and the bulb blinked on, revealing two more children crowded into the back of the closet.

From "Out of Darkness" by Ashley Hope Pérez