E-73: An Antitumor Substance. Part I. Isolation and Characterization¹

Abstract

E-73, AN ANTITUMOR SUBSTANCE 1127 e n t on qualitative color tests and on Rf. The periodate oxidation information given is difficult to interpret in terms of a unique structure. Quantitative data on the amounts of formaldehyde liberated during periodate oxidation before and after reduction with borohydride would be useful in determining whether the compound tested and found t o be inactive in hemagglutination inhibition tests in the blood group B system was galactose linked a t o the 6 carbon of N-acetylglucosaniine : inhibition of precipitation, which is a more sensitive test, was not carried out. The fucose in blood group B substance from ovarian cyst appears to be linked very differently from the fucose in blood group A and O(H) substances from hog gastric mucin. Only 45 mg. of free fucose (2.6yQ) of 1.7 g. dialysable constituents were found when ovarian cyst B substance was hydrolyzed a t fiH 1.G for 2 hr. a t looo, whereas -17 to 9570 of the fucose in the dialysate was free when hog gastric mucin was treated similarly.'O h blood group A substance derived from human ovarian cyst fluid and partially hydrolyzed a t pH 1.9 also liberated most of the dialysable fucose as free fucose."5 These observations would suggest that part of the fucose in blood group h substance is linked quite differently from that in blood group B substance. 'rhus if the hypothesis of Watkins and were correct that A and B substances are derived from H substance under the influence of the X and B genes, respectively, these genes would also have to modify the fucose portion of the H substance in addition to introducing the specific A and B oligosaccharides side chains to account for the differences in lability of the fucose. Moreover, the findings that the Pl fractions' liberated by mild acid hydrolysis of B and A substance give rise to antibodies which were different in specificity from each other and from the original A and B substances also indicate that the genes determining A or B specificity control other steps in the synthesis of their respective substances in addition to the synthesis of the specific oligosaccharide side chains which are recognized using anti-A and anti-B serum.(35) Unpublished observations. (36) W. M. Watkins and W. T. J. Xorgan, Vox Sanguinis, 4, 97 (1959). SEWThe isolation of E-'73 with antitumor properties together with two diastereoisomeric forms of cycloheximide, fungicidin and two inert crystalline compounds from the culture filtrates of Streptomyces albulus is described.In our cancer-screening program, a new species of actinomycete was isolated from the soil by our microbiology division. Broths from this culture, when tested a t the Sloan-Kettering Institute as well as a t our laboratories showed significant activity against mouse Sarcoma 180 and against human tumor transplants grown in rats. This organism was designated as Streptomyces alhulus,2 and the isolation of the active principle is reported here.The organism is grown in the usual natural media in submerged culture for 3-6 days. The broths are active...

Biological properties of streptonigrin derivatives. III. In vitro and in vivo antiviral and antitumor activities.

“…A mixture of the upper and lower components of the aamino acid derivatives was employed for the measurement of their biological activities since both diastereoisomers were identical to each other in terms of the biological properties as can be seen in Table 1. The hydrazide, amides and amino acid derivatives inhibited AMVreverse transcriptase to the sameextent as STN-COOH (1); the ID50 values were in the range of 2~8 //g/ml. Up to 4 Atg/ml, the highest concentration tested, the inhibition of cell growth was not significant with the amino acid derivatives.…”

Biological properties of streptonigrin derivatives. I. Antimicrobial and cytocidal activities.

“…While streptonigrin methyl ester (2) showed marked antitumor activity by parental administration as well as 1, the maximum tolerated dose of 2 for humans was 5 ti 6 times that of 19,10). Therefore, the carboxyl group on C2' of 1 was modified by the acid chloride method using acid chloride of 1 as an intermediate (Method A) or by the reaction of an amine with 1 in the presence of phenyl bis(2- Fig.…”

Purification and characterization of S-adenosylhomocysteine deaminase from streptonigrin-producing Streptomyces flocculus

“…An S-adenosylmethionine-dependent methyltransferase found in Streptomycesflocculus converts tryptophan to P-methyltryptophan (5), thereby committing tryptophan to the biosynthesis of the potent antitumor antibiotic streptonigrin (12).…”