Dissolved combined amino acids

Middleboe, M., N. H. Borch, and D. L. Kirchman. 1995b. Bacterial utilization of dissolved free amino acids, dissolved combined amino acids and ammonium in the Delaware Bay estuary Effects of carbon and nitrogen limitation. Marine Ecology Progress Series 128 109-120. 

Keil, R. G., and D. L. Kirchman. 1993. Dissolved combined amino acids Chemical form and utilization by marine bacteria. Limnology and Oceanography 38 1256—1270. 

DFAA, dissolved free amino acids DCAA, dissolved combined amino acids TDCHO, total dissolved combined carbohydrates DPA, dissolved primary amines. 

Figure 8.5 Experimental fluxes of NELt-1-, NO3U dissolved organic nitrogen (DON), urea, dissolved free amino acids (DFAA), and dissolved combined amino acids (DCAA) across the sediment-water interface in cores collected in Hog Island Bay (USA). (Modified from Tyler et al., 2003.)...

The decay of proteins and amino acids in phytoplankton cultures, under oxic and anoxic conditions, indicated very little selectivity (Nguyen and Harvey, 1997). However, 15 to 95% of the total particulate amino acid pool consisted of polypeptides/proteins in anoxic treatments versus 8 to 65% in oxic conditions. The similarity of particulate amino acid composition during phytoplankton decay agrees with other work in the Delaware Bay estuary (USA), which showed similar composition in the dissolved combined amino acid (DCAA) pool (Keil and Kirchman, 1993). 

Allochthonous DON sources from terrestrial runoff, plant detritus leaching, soil leaching, sediments, and atmospheric deposition may also represent important inputs to estuaries (Berman and Bronk, 2003). DON typically represents about 60 to 69% of the TDN in rivers and estuaries (Berman and Bronk, 2003). The major components of DON include urea, dissolved combined amino acids (DCAA), DFAA, proteins, nucleic acids, amino sugars, and humic substances (Berman and Bronk, 2003). However, less than 20% of DON is chemically characterized. 

Keil, R., and Kirchman, D. (1991b) Dissolved combined amino acids in marine waters as determined by vapor-phase hydrolysis method. Mar. Chem. 33, 243-259. 

SommerviUe, K., and Preston, T. (2001). Characterisation of dissolved combined amino acids in marine waters. Rapid Communications in Mass Spectrometry 15, 1287—1290. 

J0rgensen, N. O. G., andjensen, R. E. (1997). Determination of dissolved combined amino acids using microwave-assisted hydrolysis and HPCL precolumn derivatization for labeling of primary and secondary amines. Mar. Chem. 57, 287-297. 

Robertson, K. Williams, P. Bada, J. Acid hydrolysis of dissolved combined amino acids in seawater a precautionary note. LimnoL Oceanog. 1987, 32, 996-997. 

At the present it is estimated that the concentration of dissolved combined amino acids lies 4 to 5 times higher than that of DFAA (Garrasi et al., 1979). 

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