Some Characteristics of a Lipase Preparation from the Uredospores of Puccinia graminis tritici.

The characteristics of a lipase preparation from the uredospores of Puccinia graminis (pers.) f. sp. tritici (Eriks. and Henn.) have been investigated. The majority of the lipolytic activity in disrupted uredospores was found to be associated with a lipid-containing, particulate fraction which sedimented at 5000g. With triolein as a substrate, both 1,3- and 1,2-diglycerides were formed. Ethylenediaminetetraacetate, p-chloromercuribenzoic acid, and Hg(2+) strongly inhibited the activity. A pH optimum of 6.7 was observed. The sensitivity of the preparation to higher temperatures was indicated by a complete loss of activity when the preparation was preincubated at 25 C or above for 30 minutes. A temperature optimum of 15 C for the enzyme is strikingly similar to the temperature optimum for germination of the uredospores. The possible relationship between the sensitivity of the enzyme and the germination process is discussed.