variant of glyco-: glucoprotein.
Also especially before a vowel, gluc-.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
before vowels, gluc-, word-forming element used since c.1880s, from Greek glykys "sweet" (see glucose). Now usually with reference to glucose.
Online Etymology Dictionary, © 2010 Douglas Harper
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.