Hydrolysis of peripheral leucine enkephalin in allergic asthma

Plasma hydrolysis of leucine enkephalin was studied in a group of patients affected by seasonal allergic asthma in acute and quiescent stage; data wer e compared with those obtained from a control group of healthy volunteers. Results obtained indicate a statistically significant reduction of leu-enke phalin hydrolysis in allergic subjects. In the quiescent stage, substrate d egradation is reduced, and the pattern of the hydrolysis by-products is mod ified with respect to normal controls. In the acute stage, hydrolysis is fu rther reduced, and the pattern of the hydrolysis by-products is further mod ified with respect to the quiescent stage. The variations of leu-enkephalin hydrolysis appear to be controlled by decreased activity of proteolytic en zymes and by increased activity of the low-molecular-weight plasma inhibito rs active on these enzymes. The sum of these processes is conducive to a di stribution of enkephalin-hydrolyzing enzymes, as well as a hydrolysis patte rn, that appears to be specific for the allergic subjects and distinct from that seen in the controls. (C) 1999 Academic Press.