analog

1. One of two organs or parts in different species of animals or plants which differ in structure or development but are similar in function.

2. A compound that resembles another in structure but is not necessarily an isomer (e.g., 5-fluorouracil is an analog of thymine); analog’s are often used to block enzymatic reactions by combining with enzymes (e.g., isopropyl thiogalactoside vs. lactose). Syn: analogue.

Origin

[G. analogos, proportionate]

enzyme analog