What are the different names of proteins?

December 28, 2025 •

3 min read

Every living organism relies on proteins, which are a class of macromolecules found in all cells. The average human body contains over 100,000 different types of proteins, each with a specific function. Consequently, these versatile molecules are referred to by many different names, reflecting their diverse roles and properties.

Quick Summary

The many names for proteins, including polypeptides, enzymes, and hormones, are based on their function, structure, or origin. Protein classification can be highly specific, ranging from general types like structural proteins to individual examples like albumin or keratin.

Key Points

Functional Classification: Proteins are named for their biological function, such as enzymes, hormones, structural, and transport proteins.
Structural Classification: Protein names can also describe their physical shape, separating them into globular (compact) or fibrous (elongated) proteins.
Polypeptides: At its most basic level, a protein is a chain of amino acids known as a polypeptide.
Compositional Names: Some protein names, like glycoproteins and metalloproteins, reflect a combination of amino acids and a non-protein prosthetic group.
Gene and Protein Names: In scientific contexts, protein names often correspond to their gene name, with specific capitalization and italicization rules.
Consistent Nomenclature: Standard guidelines, such as those from UniProt, are used to ensure protein naming is consistent and unambiguous across scientific databases.

Protein Classifications Based on Function

Proteins are often named based on their biological function, which helps organize the vast number of different proteins in the body.

Enzymes: The Catalytic Proteins

Enzymes are a major functional class of proteins that act as biological catalysts, accelerating biochemical reactions without being used up. Their names commonly end in '-ase', such as lactase and amylase.

Structural Proteins

Providing support and maintaining shape, structural proteins are vital for cells and tissues. Examples include:

Collagen: Found in connective tissues like skin and bones.
Keratin: A component of hair, nails, and skin.
Actin and Myosin: Involved in muscle contraction.

Transport Proteins

These proteins facilitate the movement of molecules and ions within the body or across cell membranes. Key examples are:

Hemoglobin: Carries oxygen in the blood.
Albumin: Transports various substances in the blood.
Transferrin: Responsible for iron transport.

Hormonal Proteins

Protein-based hormones function as signaling molecules in the endocrine system. Examples include:

Insulin: Regulates blood sugar.
Glucagon: Increases blood sugar by breaking down glycogen.

Protein Nomenclature Based on Structure and Composition

Proteins can also be named or classified according to their physical characteristics and chemical makeup.

Polypeptides

A protein is fundamentally a polypeptide, a chain of amino acids linked by peptide bonds. This term emphasizes the basic structure of the molecule.

Simple vs. Conjugated Proteins

Based on composition, proteins are simple if they contain only amino acids (like albumin) or conjugated if they include a non-protein part called a prosthetic group. Conjugated proteins are often named after their prosthetic group, such as glycoproteins (with carbohydrates) or metalloproteins (with metal ions).

Globular vs. Fibrous Proteins

Protein shape provides another classification method. Globular proteins are compact and often function as enzymes or transporters, while fibrous proteins are elongated and typically serve structural roles, like collagen and keratin.

Comparison Table of Protein Names and Characteristics


Classification Type	Examples	Defining Characteristic	Key Role	Example Context
Functional	Enzymes, Hormones	Named by biological task	Catalysis, signaling	Amylase breaks down starch.
Structural	Collagen, Keratin	Named by physical support role	Framework, support	Collagen provides skin elasticity.
Compositional	Glycoproteins, Lipoproteins	Named by chemical makeup	Transport, immunity	Lipoproteins move fats in the bloodstream.
Shape-based	Globular, Fibrous	Named by physical form	Compact vs. elongated	Globular proteins often act as enzymes.
Biochemical	Polypeptide	Named by monomer chain	Fundamental building block	The basic term for a protein molecule.

The Naming Convention for Protein Genes

Scientific protein nomenclature can be intricate due to the relationship with gene names and the existence of aliases. Guidelines exist to ensure consistency. Gene symbols are frequently used to refer to proteins, with capitalization rules varying between species. For instance, the human gene IGF1 (italicized) corresponds to the protein IGF1 (non-italicized). This highlights the link between the gene, its messenger RNA, and the resulting protein.

Conclusion

The extensive list of protein names reflects their diverse functions and essential roles in biology. Nomenclature is systematically based on function, structure, and composition. From the fundamental 'polypeptide' to specific categories like 'enzymes' or individual proteins like 'hemoglobin', each name offers clues about the molecule. Understanding these naming conventions is crucial for studying biochemistry and molecular biology.

Learn more about protein naming conventions through UniProt's guidelines.

Frequently Asked Questions

The most basic name for a protein is a polypeptide, which refers to the long chain of amino acids that make up the molecule.

Enzyme names often end in '-ase' as a standardized suffix to indicate their function as a biological catalyst. For example, lipase digests lipids, and protease digests proteins.

Common structural protein names include collagen, which is found in connective tissues, and keratin, which forms hair and nails.

The terms are often used interchangeably, but a polypeptide is technically a single chain of amino acids. A protein can be made of one or more polypeptide chains.

Hemoglobin and albumin are both transport proteins, named for their specific function. Hemoglobin transports oxygen, while albumin carries various substances in the blood.

A simple protein, or homoprotein, consists only of amino acids. A conjugated protein, or heteroprotein, contains a non-amino acid component called a prosthetic group, which influences its name, such as a glycoprotein.

Protein names in a scientific context often derive from their corresponding gene names. Standard conventions govern capitalization and formatting, with the gene symbol often being capitalized and italicized, while the protein is capitalized and not italicized.