Abnormal circulating enzyme concentration or activity Decreased lecithin cholesterol acyl transferase level 2017-04-23T16:31:33Z Lecithin cholesterol acyl transferase (LCAT) is a plasma enzyme which esterifies cholesterol, and plays a key role in the metabolism of high-density lipoprotein cholesterol (HDL-C). Reduced level of the enzyme lecithin cholesterol acyl transferase.