Bovine adrenodoxin was cross-linked to adrenodoxin reductase with 1-ethyl-3-(3-dimethyl-aminopropyl) carbodiimide. Mass spectrometry showed the reaction product to be a 1:1 complex of the two proteins with M(r) = 64,790 +/- 50. The cross-linked complex showed cytochrome c reductase activity and could be crystallized by hanging-drop vapor diffusion. Crystals of the adrenodoxin-adrenodoxin reductase complex are hexagonal, space group P6(1)22 or P6(5)22, with a = 93.26 A and c = 612.20 A and diffract to 2.9 A resolution at 100 K. Assuming two cross-linked complexes per asymmetric unit yields a reasonable V(M) of 2.97 A3/Da.

Bovine adrenodoxin was cross-linked to adrenodoxin reductase with 1-ethyl-3-(3-dimethyl-aminopropyl) carbodiimide. Mass spectrometry showed the reaction product to be a 1:1 complex of the two proteins with M(r) = 64,790 +/- 50. The cross-linked complex showed cytochrome c reductase activity and could be crystallized by hanging-drop vapor diffusion. Crystals of the adrenodoxin-adrenodoxin reductase complex are hexagonal, space group P6(1)22 or P6(5)22, with a = 93.26 A and c = 612.20 A and diffract to 2.9 A resolution at 100 K. Assuming two cross-linked complexes per asymmetric unit yields a reasonable V(M) of 2.97 A3/Da.

Two amylolytic active protein fractions (named α‐amylase 1 and α‐amylase 2) were isolated from the bacterium Thermoactinomyces vulgaris strain 94‐2A. α‐Amylase 1 had a molecular mass of 51.6 kDa, whereas α‐amylase 2 consists of two fragments which have molecular masses of 17.0 and 34.6 kDa, respectively. These two fragments are products from a proteolytic cleavage of a‐amylase 1 at amino acid position 303 (tryptophan) by a serine protease (thermitase) which is also produced by T. vulgaris. The purified α‐amylase 1 and 2 follow the Michaelis‐Menten kinetics in the presence of starch as substrate with Km values of 1.37 ± 0.07 and 1.29 ± 0.18 mg/mL, respectively. In effect they differ in their stability characteristics. The amino acid sequence of α‐amylase from T. vulgaris derived from DNA sequence (1) was compared with those of other α‐amylases. It reveals high homologies to α‐amylases from other microorganisms (e.g. B. polymyxa, A. oryzae, S. occidentalis and S.fibuligera). A three‐dimensional structure model for α‐amylase 1 on the basis of the 3 Å X‐ray structure of Taka‐amylase was constructed.