Specificity of a neutral Zn-dependent proteinase from Thermoactinomyces sacchari toward the oxidized insulin B chain.
The proteolytic specificity of the neutral Zn-dependent proteinase from Thermoactinomyces sacchari was determined by analysis of the peptides obtained after incubation with the oxidized insulin B chain as a substrate. The enzyme is an endopeptidase with broad specificity. In total, 12 peptide bonds in the B chain of insulin were hydrolyzed. The major requirement is that a hydrophobic residue such as Leu, Val, or Phe should participate with the alpha-amino group in the bond to be cleaved. However, hydrolysis of bonds at the N-terminal side of His, Thr, and Gly was also observed. The peptide bond Leu 15-Tyr 16 in the oxidized insulin B chain, which is the major cleavage site for the alkaline microbial proteinases, is resistant to the attacks of the enzyme from Thermoactinomyces sacchari and other neutral proteinases. The proteolytic activity of the Zn-dependent proteinase from T sacchari is different from those of other metalloendopeptidases from microorganisms.
Institute of Organic Chemistry, Bulgarian Academy of Sciences, Sofia.
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DN
Georgieva
S
S
Stoeva
V
V
Ivanova
A
A
Gusterova
W
W
Voelter
D000595:Amino Acid Sequence; D000596:Amino Acids / Q000737:chemistry; D007328:Insulin / Q000737:chemistry / Q000378:metabolism*; D008666:Metalloendopeptidases / Q000737:chemistry / Q000378:metabolism*; D008848:Micromonosporaceae / Q000201:enzymology* / Q000378:metabolism; D008969:Molecular Sequence Data; D010084:Oxidation-Reduction; D010446:Peptide Fragments / Q000737:chemistry; D013379:Substrate Specificity; D015032:Zinc / Q000737:chemistry / Q000378:metabolism*
D000596:Amino Acids; D007328:Insulin; D010446:Peptide Fragments; D008666:Metalloendopeptidases; D015032:Zinc