10.22376/ijpbs.2019.10.1.p1-12 Volume 10 Issue 2 2019 (April-June) The activity and de-staining property of plant proteases from the sources such as Eucalyptus leaves, Eucalyptus seeds, and Neem fruits were studied and their protein content was determined. The highest protein content and protease activity was present in the leaves of Eucalyptus followed by Eucalyptus seed and Neem fruit. The optimum temperature for the activity of protease for all three samples was around 40°C and the crude extract of Neem fruit showed its maximum activity at acidic pH of 5. Eucalyptus seeds showed its maximum activity at pH 6 and Eucalyptus leaves showed its maximum activity at pH 7. The crude extract of Eucalyptus leaves showed greater K lessThan sub greaterThan m lessThan /sub greaterThan and V lessThan sub greaterThan max lessThan /sub greaterThan having values 0.02 mM/lit and 4.761 µM/sec respectively, followed by Eucalyptus seeds having values of Km and V lessThan sub greaterThan max lessThan /sub greaterThan as 0.0067 mM/lit and 1.127 µM/sec respectively and Neem fruit having the values of Km and V lessThan sub greaterThan max lessThan /sub greaterThan as 0.00151 mM/lit and 0.758 µM/sec respectively. The specific activity of partially purified extract of Eucalyptus leaves at 30% salt saturation was greater when compared to Eucalyptus seeds and Neem fruit whose individual specific activity was high at 90% and 30% salt saturation respectively. We have also reported that the crude enzymes could also remove stains (roli, turmeric, tea, coffee and ink) from a stained cloth. Among the three samples, Eucalyptus leaves showed better de-staining property which can provide cheaper enzyme source and wider commercial use as an additive in the detergent industry. SUNITA SINGH, SARVESH RAGHAV, KEERTHANA KALYANARAMAN AND AMAN SAIFI Protease, Protease activity, Eucalyptus, Neem, De-staining property 170-174