Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.21.1 (chymotrypsin)
 10,938 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The contractile properties and myofibrillar protein composition of fast muscle have been characterized in pure strains of two tropical fish Oreochromis niloticus and O. andersoni. Single fast muscle fibres were isolated from the abdominal myotomes and chemically skinned. The maximum tension-temperature relationships of fibres were similar at 25-30 degrees C, but diverged below 17 degrees C. At 10 degrees C, maximum tension was around 60% higher in O. andersoni (160 +/- 15 kN m-2) than O. niloticus (105 +/- 13 kN m-2) (mean +/- SD). The myofibrillar protein composition of fast fibres was investigated using one-dimensional and two-dimensional gel electrophoresis and peptide mapping. The two Oreochromis species differed with respect to the composition of myosin light chains, troponin I and myosin heavy chains (V8 protease and chymotrypsin peptide maps). An unexpected finding was the presence of two isoforms of myosin light chain 1 in O. andersoni, with apparent molecular masses of 27.5 kDa (LC1f1) and 26.9 kDa (LC1f2). Individuals with LC1f1 (n = 20) and LC1f1 + LC1f2 (n = 12) were represented in the population studied. The myosin light chain 3 (LC3f) content of fibres was similar in both cases. Breeding experiments established that these intra-specific variations in isoform composition were heritable. Fast muscle from O. niloticus and O. andersoni contain two isoforms of troponin I (TNIfl + TNIf2) which were both expressed in single fibres. The identity of TNI was confirmed using a stationary phase troponin-C affinity column. Of the 20 O. niloticus studied seven contained only TNIf1.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Inter- and intra-specific variation in myosin light chain and troponin I composition in fast muscle fibres from two species of fish (genus Oreochromis) which have different temperature-dependent contractile properties. 193 7

The position of the N terminus of myosin light chain 1 (LC1) and myosin light chain 2 (LC2) of rabbit skeletal muscle was mapped on the myosin head with a monoclonal antibody (SI304), which recognized the amino acid sequence N-trimethylalanyl-prolyl-lysyl-lysyl at the N terminus of LC1 and LC2. The complex of the antibody and myosin was observed by electron microscopy. By selective cleavage of the N terminus of LC1 or LC2 with papain or chymotrypsin, the position of the N terminus of LC1 and LC2 was determined separately. The N terminus of LC2 is located at the head-rod junction. The N terminus of LC1 is 11 nm (+/- 3 nm, standard deviation) from the head-rod junction. This position is near the actin-binding site of the myosin head.
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PMID:Position of the amino terminus of myosin light chain 1 and light chain 2 determined by electron microscopy with monoclonal antibody. 244 Oct 72