Urea Cycle Urea is the major end product of nitrogen catabolism in humans. Urea synthesis is a cyclic process. Synthesis of 1 mol of urea requires 3 mol of …
Deamination While ammonia, derived mainly from the a-amino nitrogen of amino acids, is highly toxic, tissues convert ammonia to the amide nitrogen of nontoxic glutamine. Subsequent deamination of glutamine …
Transamination (Importance Of Transaminases) The first step in the catabolism of most L-amino acids, once they have reached the liver, is removal of the a-amino groups, promoted by enzymes …
Specialized Products of Amino Acids Phenylalanine, Tyrosine Phenylalanine Phenylalanine is first converted to tyrosine. Hyperphenylalaninemias arise from defects in phenylalanine hydroxylase itself (type I, classic phenylketonuria or PKU), in …
Digestion And Absorption Of Proteins Several groups of enzymes catalyze the digestion of proteins. There are two main classes of proteolytic digestive enzymes (proteases), with different specificities for the …
Functions Of Proteins Proteins are the agents of biological function. Virtually every cellular activity is dependent on one or more particular proteins. Thus, a convenient way to classify the …
The Levels Of Protein Structure The various levels of protein structural organization are defined as follows. Primary Structure The amino acid sequence is the primary (1°) structure of a …
Protein Proteins are a diverse and abundant class of biomolecules, constituting more than 50% of the dry weight of cells. This diversity and abundance reflect the central role of …
