beta-NGF-endopeptidase: structure and activity of a kallikrein encoded by the gene mGK-22.
Mouse nerve growth factor (NGF) is cleaved at a histidine-methionine bond to release an NH2-terminal octapeptide (NGF1-8). The enzyme responsible, beta-NGF-endopeptidase, is structurally and functionally similar to gamma-NGF and epidermal growth factor-binding protein (EGF-BP) and cleaves mouse low molecular weight kininogen to produce bradykinin-like activity. These data have suggested that, like gamma-NGF and EGF-BP, beta-NGF-endopeptidase is a mouse glandular kallikrein. Evidence for a physiological role for NGF1-8 encouraged studies to further characterize the structure and function of this enzyme. Purified beta-NGF-endopeptidase migrated as a single band on isoelectric focusing and reducing SDS-polyacrylamide gels. As was expected, it removed NGF1-8 from NGF. Interestingly, enzymatic activity on an artificial substrate, and on NGF, was inhibited by NGF1-8 and by bradykinin. These studies further supported the view that beta-NGF-endopeptidase acts on both NGF and kininogen. The first 30 NH2-terminal amino acids of beta-NGF-endopeptidase were sequenced. This analysis demonstrated that the enzyme is encoded by the gene designated mGK-22 (Evans et al., 1987). The sequence of this gene corresponds to that of EGF-BP type A (Anundi et al., 1982; Drinkwater et al., 1987), and so studies were performed to determine whether or not beta-NGF-endopeptidase participates in EGF complex formation. Chromatographic and kinetic data gave no evidence that beta-NGF-endopeptidase is an EGF-binding protein. Our studies suggest that contamination of high molecular weight (HMW) EGF preparations with beta-NGF-endopeptidase erroneously led to earlier designation of the product of mGK-22 as an EGF-BP.(ABSTRACT TRUNCATED AT 250 WORDS)
Fahnestock
M
M
Department of Neurology, University of California, San Francisco 94143.
Woo
J E
JE
Lopez
G A
GA
Snow
J
J
Walz
D A
DA
Arici
M J
MJ
Mobley
W C
WC
D000595:Amino Acid Sequence; D000818:Animals; D004815:Epidermal Growth Factor / Q000378:metabolism; D007610:Kallikreins / Q000235:genetics*; D007700:Kinetics; D008297:Male; D051379:Mice; D008969:Molecular Sequence Data; D009414:Nerve Growth Factors / Q000737:chemistry / Q000235:genetics*; D013329:Structure-Activity Relationship; D020840:Tissue Kallikreins
D009414:Nerve Growth Factors; D004815:Epidermal Growth Factor; D007610:Kallikreins; D020840:Tissue Kallikreins