Isoelectric point is at pH 4.1. It is precipitated by the usual protein- 

 precipitating agents such as trichloracetic acid, ammonium sulphate, alcohol, 

 and sulphosalicylic acid. Average value of elements was: N 12%, P 0.25%, 

 S 1.6%, C 42.5%, and H 7%. Hydrolysate contained 18 amino acids. - J.L.M. 



1493 



Prescott, B., and C. P. Li. 1966. 



Antimicrobial agents from sea food. Malacologia 5(1): 45-46. 



An antibacterial and an antiviral substance termed paolin 1 and paolin 2 

 respectively have been isolated from Mercenaria mercenaria. Paolin means 

 abalone extract in Chinese. The paolins seem to be relatively non-toxic 

 in a limited number of animal experiments. Antibacterial activity was 

 tested against Staphylococcus aureus, Streptococcus pyogenes, and Salmonella 

 typhi. Gram positive and gram negative organisms were inhibited by 20 pg/ml 

 of paolin 1. Paolin 2 inhibited the early phase of multiplication of 

 poliovirus, influenza B virus, or herpes simplex virus in tissue culture, 

 reducing the virus yield by more than 90%. - J.L.M. 



1494 



Prescott, B. , C. P. Li, E. C. Martino, and G. Caldes . 1964. 



Isolation and characterization of antiviral substance from marine animals. 

 Federation Proc. 23: 508 (abstract 2441). 



Antiviral substance has been extracted from Venus mercenaria and 5 other 

 marine mollusks. Acetic acid extract of oysters had antiviral activity. 

 The same extract purified by fractional precipitation with various con- 

 centrations of alcohol also reduced viral activity in mice. The product 

 was a white powder, water soluble, heat stable, resistant to digestion by 

 pepsin and trypsin, and precipitated by all protein precipitants . It has 

 a sedimentation constant of 1.6 S and a molecular weight tentatively 

 estimated at 30,000. No pyrimidines or purines were detected, and no 

 significant quantity of P was present, showing that antiviral activity is 

 not caused by any adhering nucleic acid. - J.L.M. 



1495 



Prescott, B., M. L. King, G. Caldes, C. P. Li, and A. M. Young. 1974. 



Characterization of an antitumor substance from clam (Mercenaria mercenaria) 

 liver. Internatl. J. Clin. Pharmacol. Ther. Toxicol. 9(1): 1-5. 



Schmeer (1964), abstracted elsewhere in this bibliography, was the first to 

 show that a substance which she named mercenene , extracted from Mercenaria 

 mercenaria, could prevent development of tumors in mice. Antimicrobial 

 substances isolated from mollusks had been designated as paolins. Paolin I 

 was the antibacterial fraction, Paolin II the antiviral component. The study 

 reported here found that the antitumor substance may consist of polypeptides, 

 carbohydrates and unidentified components which may be the active principle. 

 It is suggested that the active material includes several distinct components. 

 If the unknown component is the active principle, the protein molecules 

 combined with an unidentified prosthetic group may be a carrier or an 

 inhibitor so that conversion of bound active material to the free form is 

 necessary for greater antitumor activity. The greater activity of some 

 batches may have been caused by splitting-of f of active component from the 

 protein carrier during fractionation, or by removal of inhibitors. 

 (Abstracter's note: our records show that Schmeer published a paper in 196 3 

 which referred to antitumor properties of hard clam extract.) - J.L.M. 



417 



