Nitrogen metabolism during synchronous growth of chlorella. II. Free-, peptide-, and protein-amino acid distribution

✍ Scribed by Theodore A. Hare; Robert R. Schmidt

• Publisher: John Wiley and Sons
• Year: 1970
• Tongue: English
• Weight: 727 KB
• Volume: 75
• Category: Article
• ISSN: 0021-9541
• DOI: 10.1002/jcp.1040750109

✦ Synopsis

Abstract

The levels of free‐, peptide‐, and protein‐amino acids were measured during the synchronous growth and division cycle of a thermophilic strain of Chlorella pyrenoidosa. Most of the protein amino acids exhibited little periodism (as % of total cellular‐N); however, the free‐ and peptide‐amino acids showed a variety of dramatic changes in level during the cell cycle.

Fractionation of the acid‐soluble peptides by Sephadex gel‐filtration showed that an average of only 2.8% of the peptide amino acids were associated with peptides of high molecular weight (> 5000), while approximately 75% of the peptide amino acids were components of low molecular weight peptides (< 700). The low molecular weight peptides were predominately made up of relatively few amino acids (i.e., alanine, glutamate, lysine, glycine and arginine accounted for approximately 92% of the low molecular weight peptide amino acids).

Several experiments revealed that nucleotide‐peptides do not contribute significantly to the pool of acid‐soluble peptides during the cell cycle of this organism.