APPLICATIONS OF UESULTS OF RESEAR< III. 



365 



implements to carry oirl operations thai are essential 

 to their existence, and uch enzymes arc modifiable id 

 quantity and quality in accordance with changes in 

 internal and external conditions. The nature of both 

 reactions and products of enzymic action depends upon 

 the constitution and composition of the physico-chemi- 

 cal mechanism of which the enzyme is an integral part. 

 Whether or not at each step of serial reai tions a pori on 

 of pre-existing enzyme is merely modified or a hi b 

 enzyme is formed which constitutes an essential part 

 ei the particular phase of the reactions is not known, 

 hut that one or the other occurs is apparently withoul 

 question. It has long been established that some of the 

 lower organisms, such as the yeast plant, have the prop- 

 erty of modifying the characters of the enzymes pro- 

 duced in relation to varying conditions; recent studies 

 of the animal organism show that the same phenomenon 

 occurs in both tissues and blood; and our knowledge 

 of the processes concerned in the catabolism and ana- 

 bolism of complex substances, such as starch, is fully in 

 support of such a conception. In other words, as each 

 step of development is reached the alterations which 

 occur in the physico-chemical mechanism absolutely 

 automatically predetermine the characters of the changes 

 of the next succeeding step, and so on to the end. Hence 

 it follows that the peculiarities of any given physico- 

 chemical mechanism predetermine the characters of the 

 phenomena which ensue under given conditions. 



An illustration of the probable modus operandi of 

 such a mechanism is found in the phenomena of the 

 synthesis and analysis of starch: During the production 

 of -tarch through the agency of the chloroplast or leuco- 

 plasl we conceive that there are instituted a predeter- 

 mined, orderly, independent and interdependent series 

 of reactions, the first of which is manifested in an inter- 

 action between water and carbon dioxide through the 

 agency of an enzyme in the form of an oxidase to form 

 formaldehyde. During this process there is formed an- 

 other enzyme, which tentatively may be designated an 

 aldehydase, that reacts with formaldehyde and by poly- 

 merization and condensation of six molecules gives rise- 

 to a simple sugar, such as dextrose. At the same time 

 another enzyme appears in the form of maltase, which, 

 reacting with the dextrose causes the formation of mal- 

 tose, during which reaction another enzyme, a '■ 

 trinase, is produced which reacts with the maltose to 

 yield dextrin. Going on with this reaction, another 

 enzyme which may be designated an amylase appears, 

 which, reacting with the dextrin, forms soluble starch. 

 During this stage there arises another enzyme, a a 

 lase, which converts the starch from the soluble to the 

 insoluble form or ordinary starch. At this stage the 

 -eric- of reactions have readied their end because a 

 state of physico-chemical equilibrium has become estab- 

 lished, the ultimate purpose of the processes being 

 attained, that i-. a form of pabulum of extremely high 

 nutritive value and of extremely low molecular pressure, 

 even in soluble Eorm, so that it may entirely and rapidly 

 disappear without disturbance of phi mical equi- 



librium in the starch-bearing ci lis. The mechanism con- 

 cerned in starch-formation is without doubt paralleled 

 in thi' synthesis of protein-, fats, and other complex 

 organic substances, and ii is bui a -top from the indi- 

 vidual serial p concerned in the formation of 



each of these substances to a iated 



there are formed and combined the various Bubsta 

 that constitufc janic structural components of 



protoplasm. Moreover, such serial processes are i 

 sible at an\ tag and o simple a mod 

 change in the percentage of water may, a- it 

 u i ion, i ause a synthel ii 



In vitro in both synthetic and analytic processes like 

 those which constitute serial steps in the buildinj 

 and breaking down of starch, protein, fat, and ot 

 complex organii mbstai not occur ii 



reaction, as far as Known, either a tran-o or a 



production of enzyme such as occurs in vivo, I 

 when a single enzyme is present it carries out but one 

 step of the reactions, hut when, as in the case of diasl 

 as ordinarily prepared, the enzyn a single sub- 



stance or unit body but a composite of a number of 

 enzymes or modifications of a given basic enzyme, serial 

 -tops may occur as in vivo. Thus, if only a single 

 enzyme lie present formaldehyde may be converted into 

 a monosaccharose, or a moi rose into a disac- 



charose, or a disaccharose into a polysaccharoa 

 dextrin, or a dextrin into a higher form of polysaccharose 

 such as soluble starch, according to the enzyme or modi- 

 fied enzyme and initial substance preseni ; or the reverse 

 of any one of these processes may occur if proper con- 

 ditions are present, hut never do any two su 

 progressive or regress^e cur unless through the 



agency of two different enzymes or modified font 

 one enzyme which arc present. 



It will thus he apparent that the i of syn- 



thesis is determined by the character of the initial 

 physico-chemical mechanism and that all subsequent 

 reactions under given conditions are definitely prede- 

 termined; in other word-, the entire train of reactions 

 depends inherently upon the nature of the initial ph] 

 chemical mechanism of which the enz] I starts the 



serial changes is an integral part. 



Having a specific ster :hemii - ; - tern, such a sys- 

 tem in accordance with the laws of physical-chemistry 

 can exist in either a latent or act] and thai when 



in an active state the reaction or reactions are always in 

 the direction of the establishment of equilibrium of 

 solution, every reaction or -cries of reactions hein;,' as 

 definitely predetermined as is every reaction familiar to 

 the inorganic chemist. The germplasm in the form in 

 which it i- secreted ma jarded as being in the 



nature of an exceedingly complex -ten o hemic -; 

 which is from it- incipiency, or very soon is in a state 

 of physico-chemical unequilibrium, and in which, a- a 

 consequence, reactions are set up which are mam 



ially in histolo al de I pments that ultimately 

 : e the fully developed ovule, at which time a 

 -i. nc of physico-chemical equilibrium is established, as 

 i- evident by the arrested developmental activities. This 

 state of physico-chemical equilibrium of the matured 

 ovule may he instantly changed to one leading to serial 

 definite!} predetermined reactions by mem- of an acti- 

 vating substance or condition, such a- certain ions or 

 inorganic -alts, a spermatozoon, or a ne 

 initiating the firs! -top of the reactions, the nati 

 the succeeding ined primarily 



by the inherent nature of the i y^tem 



