|Xie, Hang - UNIVERSITY OF ARKANSAS|
Submitted to: Journal of Comparative Physiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 11, 2001
Publication Date: N/A
Interpretive Summary: There are many physiological events such as wound healing, growth or disease related changes in different parts of the body, that are accomplished by a family of enzymes called MMPs. These enzymes help breakdown of the proteins which build the frame work of most organs to facilitate such local 'renovations'. Our research found that these enzymes sare also present in the bile fluid of turkeys. In the absence of any known role of these enzymes in the bile we hypothesize that these may be responsible for the disgestion of raw meat and flesh proteins in birds that rely on living preys as their staples diets.
Technical Abstract: We studied the occurrence of matrix metalloproteinases (MMPs) in turkey bile using gelatin, collagen, and casein substrate zymography, 3H labeled collagen degradation assay, and gelatin-agarose affinity purification. Our results show that bile contains matrix MMPs with gelatinase, collagenase, and stromelysin-like activities with five major gelatinolytic bands corresponding to approximate molecular weights (MW) of 64-, 60-, 46-, 40- and 36-kD. On incubation with p-aminophenylmercuric acetate or thimerosal, the densities of both 64 kD and 46 kD bands decreased, leading to the broadening of the 60 kD and the 40 kD bands. Both 64 and the 60 kD bands showed collagenolytic activities whereas the caseinolytic activities appeared as diffuse bands corresponding to MW approximately 60-, 40- , and 36-kD. Using 3H-collagen as substrate, the bile enzymes showed both a time and a concentration dependent increase in its degradation which could be inhibited by EDTA, phenanthroline, and GM 6001, the MMP inhibitors, but no by serine and cysteine protease inhibitors such as phenylmethylsulfonyl fluoride (PMSF) or leupeptin. Both 60 and the 40 kD gelatinase showed affinity adsorption to a gelatin-agarose matrix. The physiological roles of bile MMPs are not clear, but their involvement in the digestive functions of birds are likely.