The jaracatiá (Jaracatia spinosa, Aubl, DC) is a native plant from Brazilian Cerrado. The fruit presents several characteristics similar to papaya fruits (Carica papaya), allowing to suppose the presence of papain in their latex. The papain is a proteolytic enzyme with large industrial application due to properties such as resistance to high temperatures, low specificity, and production of peptides in stead of aminoacids. The objective of this work was evaluate the potential of the fruits of jaracatiá as source of proteolytic enzymes and analyze the class of the enzyme by specific inhibition. The fruits were submitted to elemental analysis, caloric value determination and tanic acid presence (Hangerman and Butler, 1978). The crude extract was prepared by maceration of 1,0g of pulp for 1,0mL of buffer which pH ranging from 3.0 to 8.0. Proteolytic activity was measured following methodology described by Silva e cols. (1995), using casein as substrate. The effect of activators such as EDTA (24.2mg) and cystine (7.8mg) were tested by adding these compounds to the assay buffer. Tests of thermal stability were performed by incubating crude extract at 90ºC in time intervals ranging from 10 to 120min. The specific inhibition of the protease activity was performed by adding PMSF (2.0; 5.0 and 10.0mmolL^-1), E-64 (10.0mmolL^-1) and mercury acetate (50mmolL^-1). The elemental analysis of fruit pulp resulted in a composition of 1.9% of protein, 1.0% of lipids, 3.9% of carbohydrates and caloric value of 32.0Kcal/100g. The Hangerman/Butler test showed absence of tannins, indicating that casein precipitation was due hydrolysis by proteolytic activity. The best pH for protease extraction were 7.0 and 8.0. In this pH the activity observed was 47.5 EUmL^-1. The same protease activity was obtained in the presence of activators EDTA and cystine. Tests of thermal stability reveled that proteolytic activity remain unaffected when submitted to 90°C for 30 minutes, starting to decrease after 60 minutes of thermal treatment. The inhibition tests showed that protease was inhibited by 10.0mmolL^-1 E-64 and 50mmolL^-1 mercury acetate, indicating the presence of a cystein protease in the crude extract. These results indicate that jaracatia is a rich source of protease, probably one from cystein family, that is very promising for biotechnological application due its thermal stability.