Transient kinetic studies of protein hydrolyses by endo- and exo-proteases on a 27 MHz quartz-crystal microbalance.
We have compared endo- and exo-type protease reactions and characterized the enzymatic reaction mechanisms by determining all kinetic parameters (k(on), k(off), k(cat), K(d) = k(off)/k(on), and K(m) = (k(off) + k(cat))/k(on)) by following the mass change of the formation and the decay of the enzyme-substrate (ES) complex (k(on) and k(off)), and the formation of the product (k(cat)) on a 27 MHz quartz-crystal microbalance in aqueous solutions. The K(m) value was nearly equal to the K(d) value for the endo-type protease (subtilisin and alpha-chymotrypsin); however, in the case of exo-type protease (carboxypeptidase P), the K(m) value was quite different from the K(d) value, due to k(cat) >> k(off).
Furusawa
Hiroyuki
H
Department of Biomolecular Engineering and Frontier Collaborative Research Centre, Tokyo Institute of Technology, B-53, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8501, Japan.
Takano
Hiroki
H
Okahata
Yoshio
Y
D002918:Chymotrypsin / Q000378:metabolism; D010450:Endopeptidases / Q000378:metabolism*; D004800:Enzymes, Immobilized / Q000378:metabolism*; D020689:Exopeptidases / Q000378:metabolism*; D005087:Glucan 1,4-alpha-Glucosidase / Q000378:metabolism; D006868:Hydrolysis; D007700:Kinetics; D009211:Myoglobin / Q000378:metabolism; D011506:Proteins / Q000378:metabolism*; D011791:Quartz; D020860:Subtilisin / Q000737:chemistry; D013997:Time Factors
D004800:Enzymes, Immobilized; D009211:Myoglobin; D011506:Proteins; D011791:Quartz; D005087:Glucan 1,4-alpha-Glucosidase; D010450:Endopeptidases; D020689:Exopeptidases; D002918:Chymotrypsin; C117608:alpha-chymotrypsin; D020860:Subtilisin