xii CONTENTS 



PAGE 



Proteins as colloids 298 



Decomposition products 303 



Amino acids obtained as cleavage products of proteins . . . 305 



Constitution of the protein molecule 308 



Polypeptides 309 



Occurrence of amino acids in plants 311 



Classification of proteins ......... 312 



Comparison between vegetable and animal proteins .... 318 



Extraction of proteins 320 



Synthesis of proteins in the plant ....... 323 



Synthesis of amino acids in the plant 327 



Estimation of nitrogen ......... 330 



SECTION IX.— ENZYMES 334 



Classification 338 



Isolation ............ 339 



Chemical constitution 339 



Properties 340 



Colloidal nature of enzymes ........ 341 



Mode of action ........... 342 



Activators ............ 344 



Paralysers 346 



Anti-enzymes ........... 348 



Enzymes and the laws of mass action 351 



Consideration of certain types of enzymes ...... 355 



Lipase 356 



Isolation 357 



Quantitative determination of activity 358 



Diastase 358 



Isolation 359 



Quantitative determination of activity 360 



Proteases 360 



Isolation .......... 360 



General considerations 362 



Tryptophane reaction ........ 363 



Quantitative determination of activity 364 



Zymase and alcoholic fermentation 364 



Isolation of zymase ........ 367 



General considerations 367 



Identification of ethyl alcohol ...... 372 



Quantitative determination of activity ..... 373 



Occurrence of alcohols in plants 375 



Inosite 377 



Manufacture of ethyl alcohol 379 



Oxidases 380 



Isolation 382 



Peroxidase 382 



Preparation 382 



Identification 383 



General considerations ........ 384 



INDEX 389 



