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J G HIRSCH

Publications and source records attributed to J G HIRSCH.

45 records · Page 3Linked to original sources
PubMed1953

The essential participation of an enzyme in the inhibition of growth of tubercle bacilli by spermine.

Spermine inhibits the multiplication of tubercle bacilli in vitro only if another tissue substance is present in the culture medium. This activating substance occurs as a chemical contaminant of the albumin in commercial bovine plasma fraction V ordinarily added to culture media; it is also found in whole bovine and sheep serum and in aqueous extracts of the guinea pig kidney. No detectable spermine activator is contained in whole human, guinea pig, or rabbit serum. The serum constituent which renders spermine inhibitory for the growth of acid-fast bacteria has the properties of a protein of the alpha globulin classification. This protein is an enzyme which acts on spermine. Presumably, some product of the enzymatic reaction exerts a toxic effect on mammalian tubercle bacilli.

Animals↗
PubMed1953

Spermine oxidase: an amine oxidase with specificity for spermine and spermidine.

Sheep serum and bovine serum contain an enzyme which brings about a rapid oxidative deamination of certain biological amines. This enzyme differs from previously described amine oxidases in several regards and especially in its substrate specificity. Studies thus far indicate that only spermine and the closely related compound spermidine serve as substrates for the enzyme in sheep serum. For this reason, the enzyme has been named spermine oxidase. Spermine oxidase is active in a variety of fluids of various ionic strength and buffer composition. The reaction takes place between pH 6.0 and pH 8.0 with an optimal rate in the vicinity of neutrality. Under certain conditions, the rate of oxygen consumption during the initial phase of the reaction is independent of the concentration of substrate. The diminution in rate observed during the latter phase of the enzymatic attack appears to be due to an alteration in the kinetics at low concentrations of substrate, or to competitive inhibition by a product of the reaction. Carbonyl reagents almost completely block the action of spermine oxidase, while certain amines and the cyanide ion bring about partial inhibition. Thiol reagents and sequestering compounds do not alter the course of the oxidative process. In the presence of low concentrations of mercuric chloride, the sheep serum-spermine system consumes approximately twice as much oxygen as controls containing no mercuric ion. The mechanism by which the mercuric ion stimulates additional oxygen uptake is obscure.

Amine Oxidase (Copper-Containing)↗
PubMed1952

The effect of spermine on tubercle bacilli.

A crystalline substance capable of suppressing the growth of a variety of mycobacteria in vitro has been isolated from extracts of tissue in acidified dilute ethanol. This inhibitory material was found to be equally active against virulent, attenuated, and avirulent variants of human and bovine tubercle bacilli, but had little or no effect on saprophytic mycobacteria and on several non-acid-fast microorganisms under the conditions of the test. Its inhibitory activity on the growth of tubercle bacilli was essentially independent of the size of the inoculum within the limits studied. The crystalline material appeared to exert a bactericidal action on the susceptible organisms. Tubercle bacilli maintained in the presence of the agent for 4 days failed to grow when transferred to inhibitor-free media. The findings were not appreciably altered by minor variations in the composition of the medium or by shift in its reaction. When certain preparations of whole serum were used in the medium in place of albumin, no antimycobacterial activity was observed; however, this activity was restored by adding bovine albumin (fraction V) to the media containing whole serum. By chemical purification and analysis, the inhibitory material was identified as spermine, an organic base widely distributed in animal tissues.

Animals↗