Protoplasm : its definition, chemistry and stucture / by Gustav Mann.

  • Gustav Mann
Date:
1906
Catalogue details

Licence: In copyright

Credit: Protoplasm : its definition, chemistry and stucture / by Gustav Mann. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    alkalies, or to certain ferments acting preferably either in acid (pepsin) or alkaline (trypsin) solutions, they are broken up into smaller units called albumoses and peptones. On still further dissociating these latter we arrive at a number of substances known as amino-acids, characterized by the pre- sence of one or more carboxyl-groups (CO • OH) and one or more amino-groups (NH^), attached to a carbon chain. Ac- cording as to whether the NH^-radical is attached to the first, second, third . . . carbon-atom next the carboxyl-group we speak of a, /3, y . . . amino-acids. H H NH, I I I /OH I I -C-C—c-c( —c-c I I I ^O III H H H H H H H NH, H i- ,./0 ^OH NH, H H (t- -c H H H -C ./ \ O OH o-amino-acid. /3-amino-acid. 7-amino-acid. Now most amino-acids derived from protoplasm are a-amino-acids and are characterized by a sweet taste, a characteristic which led to the simplest of all amino-acids, namely amino-acetic acid, so abundant in gelatine or glue, receiving the name of sweet-glue or glycocoll. In addition to rt-amino-acids there are also found certain bitter amino- acids which are /8-compounds, such as the amino-valerianic acid formed during the autodigestion of the pancreas (Levene) and probably also tryptophane. There are no y-acids present in protoplasm. Enumeration of the Primary Dissociation- Products. (The numbers marked with a * have their constitutional formula given , hereafter.) I. Albumins, as occurring in the cytoplasm. A. Open-chain Amino-acids. I. {a) mono-amino-mono-carboxylic acids. *1. amino-acetic or Glycocoll CjHjNO,.
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