Читать книгу The Body at Work: A Treatise on the Principles of Physiology онлайн

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It would be straining language to term fermentation a phenomenon of life; worse, to define life as a sequence of fermentations. Yet it is safe to say that all the chemical changes carried out by living organisms are fermentations. Fermentation and the chemistry of life are almost synonymous terms.

A very large number of ferments are already known. Each has its own specific work to do: “To every fermentable substance is fitted a ferment, as a key to a lock.” It will be understood, from what has been already said regarding our inability to determine the composition of any ferment, that we cannot say whether or not these various ferments differ one from another in chemical constitution. They are classified according to their action, and not according to their nature. Those which build up are termed “synaptases” (συνάπτω, I unite); those which decompose, or hydrolyse, “diastases” (διάστασις, separation). The termination “ase” is added to the name of the substance upon which the ferment acts, except in cases in which other terms have already become so general as not to be displaceable: amylase, hydrolysing starch; sucrase, inverting cane-sugar; protease, hydrolysing proteins. Unfortunately, there is little uniformity in this nomenclature; amylopsin, invertin, pepsin, are terms used as often as those terminating in “ase.” As a distinguishing termination, “in” or “sin” is less desirable than “ase,” owing to the fact that it has been appropriated already as the termination of the names of albuminoids—e.g., gelatin, chondrin, mucin.