rijoDi ci'ioN oi" i;\/VMi:s 



187 



I hat could he precipitated I'loiu cult lire lil- 

 t tales ami by ethyl alcohol, acetone, and 

 other proteiii-precipitatiiij;- a^;eiits. The en- 

 zyme-like siil)staiic(> was distinct from the 

 easein-diti;est inn; ai^eiit . 



Amylases 



Xumerous actinomyeetos are ab!(> to hy- 

 drolyze starcli rapidly, either to the dextrin 

 stage or directly to maltose and glucose. Tlu^ 

 j)roduction of amylolytic enzymes by actino- 

 mycetes was first recorded by FcMini, who 

 found most of the aetinomycetes tested 

 capalile of producing such enzymes. These 

 results were later confirmed by \arious 

 investigators, including Caminiti. Some 

 claimed that the starch is hydrolyzed only 

 partially, not to the sugar stage. 



Krainsky made a detailed study of a large 

 number of aetinomycetes that were found 

 cajjable of producing amylase. This phe- 

 nomenon was further studied extensively by 

 W'aksman and Lieske, who observed that 

 onl>- \er3^ few aetinomycetes lack the ability 

 to produce such enzymes. 



For the screening of a large number of 

 cultures of aetinomycetes, agar media con- 

 taining starch as the source of carbon are 

 used. The plates are streaked and allowed to 

 incubate. After 5, 10, 15, and 20 days, the 

 surface of the agar is coA'ered with a solution 

 of I-KI, and the amount of starch hydro- 

 lyzed is measured by the width of the clear 

 zone around the streak. Formation of zones 

 1.0 to 1.5 cm wide after 10 days' incubation 

 is an index of good amylase production. For 

 the production of amylolytic enzjmies, inor- 

 ganic sources of nitrogen, especially nitrates, 

 appear to be preferable to organic com- 

 pounds. 



Stapp recorded that 83 per cent of all ae- 

 tinomycetes isolated from soil and belonging 

 to the genus Streptomyccs produced amylase. 

 Although the amylolytic property is char- 

 acteristic of the species, as noted by Krassil- 



niko\', the wide dist ribiil ioii of this propei'ty 

 tends to reduce its diagnostic \alue. .V single 

 aljjha type amylase was found to be produced 

 by (i\-e different st rej)t()myces species (Simp- 

 son and McC'oy, 1953). The mechanism of 

 break(l(»wii of starches by aetinomycetes is 

 (liscu.s.«ed further by lioisand Savary (1!)45). 



The amylases of aetinomycetes are al)le to 

 withstand the effect of higher temperatures 

 better than are t h(> cells of the organisms 

 producing them. Surovaya obtained a potent 

 diastatic preparation from a culture of »S'. 

 (liastaliciis. The organism was grown on a 

 potato medium, and a .sati.sfactory enzyme 

 preparation, designated as "superbiolase," 

 was obtained. This preparation was active 

 at 70 to 100°C and had an optimum pH at 

 (■).(■) to (■).7. The starch was converted first 

 into soluble form and then into dextrin. 

 Saccharification of the dextrin proceeded 

 much more slowly than the liquefaction of 

 starch. 



The hydrolysis of mannosidostreptomycin 

 to streptomycin, by various strains of S. 

 griseus, is said to be due to an amylase 

 (Christensen et al., Langlykke and Perlman). 

 Maruta and Tanaka isolated the enzyme 

 mannosidostreptomycinase by precipitation 

 of the culture broth with 1 to 2 per cent lead 

 acetate. The optimum pH for the action of 

 the enzyme was 6.8 to 7.4 and optimum 

 temperature 37°C. Certain aldohexoses, such 

 as glucose and mannose, inhibited the action 

 of the enzyme; D-sorbitol produced an ac- 

 celerative effect. In the regular streptomycin 

 fermentation b}^ S. grisevs, the content of 

 mannosidostreptomycin is high during the 

 early stages of fermentation and low in the 

 older stages. The presence of glucose in the 

 early stages represses the action of the en- 

 zyme. 



Many aetinomycetes are able to attack 

 dextrins, glycogen, and inulin and to produce 

 the corresponding enzymes. Lieske, who was 

 one of the few to study these enzyme sys- 



