Distribution of dipeptidylpeptidase III homologue in brain and vital organs in goat (Capra hircus)

Abstract

Goat brain dipeptidyl peptidase III (DPP-III) was recently purified and characterized. The crude enzyme preparation had optimum activity at alkaline pH of 8.5. The regional and subcellular distribution of this protease in brain along with its distribution in different goat tissues was investigated. The enzyme activity was associated with the cytosolic fraction when assayed using synthetic substrate Arginyl-Arginyl-4-methoxy-β-napthylamide (Arg-Arg-4mβNA). The pituitary body had the highest density of the enzyme and thalamus had the least when expressed on the basis of per gram wet tissue weight. Other regions of brain tend to have similar activtiy. Tissue distribution studies revealed that pancreas was the most enriched with DPP followed by liver, thymus, brain and parotid. Kidney, spleen, thyroid, paratyroid had similar activity whereas lung, heart, skeletal muscle, skin, eye lens and adrenal had comparatively lower activity. Prostate gland and testis were enriched in DPP III activty. In female goat fallopian tubes and ovary had higher activity as compared to the uterus. The enzyme is present in all the tested tissues. This indicates that the enzyme is constitutive thereby suggesting its role in some vitalcullular function.