• synonyms


[lak-teys, -teyz]
noun Biochemistry.
  1. an enzyme capable of hydrolyzing lactose into glucose and galactose.
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Origin of lactase

First recorded in 1890–95; lact- + -ase
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

British Dictionary definitions for lactase


  1. any of a group of enzymes that hydrolyse lactose to glucose and galactose
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Word Origin

C20: from lacto- + -ase
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

lactase in Medicine


  1. A galactosidase occurring in the intestine that catalyzes the hydrolysis of lactose into glucose and galactose.
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The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.

lactase in Science


  1. An enzyme that is found in the small intestine, liver, and kidneys of mammals and catalyzes the breakdown of lactose into galactose and glucose.
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The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.