Noun
tropocollagen (countable and uncountable, plural tropocollagens)
(biochemistry) A component of fibres of collagen in which three polypeptide chains are coiled around each other.
Tropocollagen molecule: three left-handed procollagens (red, green, blue) join to form a right handed triple helical tropocollagen. Source: Internet
What is left is known as tropocollagen. Source: Internet