TABLE 4.

Enzymatic activities of the purified tetrameric and hexameric SH

Activity assaysp act (U/mg)Turnover no. (s−1)
TetramerHexamerTetramerHexamer
NADH-K3Fe(CN)661.6a64.9a171222
NADPH-K3Fe(CN)6NDc0.6b2
H2-BV25.235.170120
H2-NAD+39.041.9109143
H2-K3Fe(CN)6102.1108.8284372
H2-NADP+NDcNDc
  • a Both tetrameric and hexameric SH exhibited NADH-H+ activity (around 1 % of the H2-NAD+ activity).

  • b No NADPH-H+ activity could be detected.

  • c ND, no activity could be determined.