Phages activity testing

Catalytic antibodies, like enzymes, must be isolated and purified to homogeneity before they can be studied. Initially this was done by using the hybridoma technique for isolation of monoclonal antibodies (Box 31-A). After induction of antibody formation by injecting a selected hapten into a mouse, large numbers of monoclonal antibodies had to be tested for catalytic activity. Even if several thousand different monoclonal antibodies were tested, only a few with catalytic properties could be found.1 Newer methods have incorporated recombinant DNA techniques (Box 31-A) and use of combinatorial libraries and phage display.) Incorporation of acidic or basic groups into the haptens used to induce antibody formation may yield antibodies capable of mimicking the acid-base catalysis employed by natural enzymes. 0... 

Calf thymus DNA, Xenopus liver DNA, and also DNA from T4 coli phage inhibit the vegetalizing factor. Heteropolymeric [poly d( A-T), poly d(G-C), poly d(I-C)] and homopolymeric (poly I-poly C, poly dA poly dT) double-stranded polynucleotides have no inhibitory activity (Table I). Melted, single-stranded chick DNA has about the same inhibitory effect as double-stranded DNA. However, it is not excluded that a partial renaturation occurs under the conditions of the test. Also, DNA, which was partially degraded by sonication, has about the same inhibitory effect as untreated DNA. 

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