Field-indicating Absorption Change in Isolated Chloroplasts

THE EFFECT OF TRYPSIN AND CHYMOTRYPSIN ON THE 519 NM FIELD-INDICATING ABSORPTION CHANGE IN ISOLATED CHLOROPLASTS 

Proteolytic enzymes have been used to investigate the location and function of some of the proteins associated with the thylakoid mei )rane, particularly the light-harvesting pigment proteins (Steinbeck et al, 

the coupling factor (CF ) (Moroney, McCarty, 1982) and the shield over the acceptor side of photosystem II (Renger et at., 1976). 

For example, trypsin has been shown to induce an increase in the rate of light-dependent electron transport which has been associated with uncoupling of photophosphorylation due to partial digestion of CFj. In addition trypsin, like dithiothreitol (DTT), stimulates the latent ATP-hydrolase activity of CFj.  

Trypsin and chymotrypsin attack bonds between different amino acids in this paper we have compared the effects of digesting thylakoid membranes with trypsin and chymotrypsin in an attempt to distinguish differential action of the two enzymes. 

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